{ "schemaVersion": "1.0.0", "constitutionVersion": "1.0.0", "createdAt": "2026-08-12T00:00:00Z", "description": "Append-only Evidence Passport records. Old revisions are immutable; corrections create a new revision and preserve the previous permalink.", "entity": { "type": "project", "id": "boston-green-line-train-protection", "title": "Green Line Train Protection System", "canonicalUrl": "https://1001smartcities.org/projects/boston-green-line-train-protection/" }, "currentRevisionId": "2026-08-27-correction-run-2", "revisions": [ { "id": "2026-08-27-claims-and-sources", "createdAt": "2026-08-27T02:33:50Z", "effectiveAt": "2026-08-27", "changeType": "baseline", "summary": "Created the first structured Evidence Passport with 8 claims and 11 source dossiers.", "preparedBy": { "type": "automation", "label": "AI-assisted evidence preparation", "humanApproved": false }, "review": { "status": "unreviewed", "by": null, "date": null, "note": "Awaiting operator and domain-expert review; publication of this revision implies neither." }, "changes": [ { "operation": "add", "path": "/evidencePassport", "summary": "Added claim-level evidence mapping and source dossiers." }, { "operation": "add", "path": "/revisionHistory", "summary": "Established a permanent, hash-addressed baseline revision." } ], "snapshotHash": "sha256:891b3e5a20d4f85f13bc2ba01fd47349044795185c61e6ad0c9e1c6e5cf22703", "snapshot": { "asOf": "2026-08-27", "projectFingerprint": "sha256:234d73811fff09c213ff7704ec4438b0b666ae5ebdee3f028bde0107106377df", "assurance": { "status": "unreviewed", "scope": "evidence-passport-revision", "statement": "AI-assisted structural preparation. This revision has not been reviewed by a human or subject-matter expert.", "machineChecks": [ "schema", "publication-diff-contract", "material-project-fingerprint", "claim-text-drift", "source-reference-resolution", "complete-source-dossier", "snapshot-hash" ] }, "projectState": { "status": "construction", "outcome": "ongoing", "evidenceGrade": "independent", "timeline": { "started": 2019, "ended": null } }, "governance": { "operator": "Massachusetts Bay Transportation Authority (MBTA)", "actorTypes": [ "utility" ], "fundingModel": "public", "fundingDescription": "MBTA capital programme", "cost": "≈US$112.5M Piper Networks contract (2025), after an US$83M contract awarded in 2019 to BBR/Stadler was abandoned in 2024 with US$18M paid", "ownership": null, "decisionRights": null, "exitConditions": null }, "claims": [ { "id": "clm-55f11bbd7f6cccc3", "field": "snippet", "text": "Boston's Green Line light rail has no system that enforces its signals or speed limits — operators simply obey them", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-d517875621c3c93e", "src-ea4bd5c1a5b6a988" ], "supportNote": "The NTSB report on the 2008 Newton collision records the precise defect: Green Line trains 'do not incorporate systems such as trip stops (mechanical arms or electrical inductors that slow or stop a train if the operator fails to respond)'. The operator's own project page describes the system being installed as one that alerts operators, not one that controls the train.", "caveat": "ntsb.gov serves the report only as a PDF and the accident page as a JavaScript shell, so no locator string could be recorded from the source itself.", "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-be6687f16b65ee7d", "field": "snippet", "text": "The MBTA is fitting ultra-wideband positioning that warns of overspeed and closing trains; the operator says 20 trains have been equipped so far", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ea4bd5c1a5b6a988", "src-50176f4d09eecf48", "src-1a7fc0bab3b6c3a0" ], "supportNote": "The February 2025 board summary describes 'Piper's Cenelec SIL-4 Ultra-Wideband positioning technology to localize trains operating both at grade and in the underground central subway areas'. The project page states 'So far, 20 trains have been equipped with the new technology', and NBC10 Boston describes the sensors and the cab display.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-9e704ffb5fe8ac43", "field": "snippet", "text": "The NTSB recommended collision avoidance in 2009", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-d517875621c3c93e" ], "supportNote": "Recommendation R-09-008 followed the fatal Newton collision of 28 May 2008, in which a train travelling about 38 mph struck the rear of another and the operator was killed; the board found that 'contributing to the accident was the lack of a positive train control system'. The recommendation was addressed to the Federal Transit Administration.", "caveat": "The NTSB recommends; it cannot order. The recommendation went to the FTA, not to the MBTA.", "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-28632db03e9f0166", "field": "snippet", "text": "a 2019 contract collapsed and was re-let to Piper Networks for $112.5M in 2025", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-efee7255e5b08ab7", "src-50176f4d09eecf48" ], "supportNote": "The Boston Globe reports an US$83M contract awarded in 2019 to BBR, later acquired by Stadler, on which the MBTA had paid about US$18M before terminating it in June 2024. The February 2025 board summary awards the replacement to Piper Networks, not to exceed US$112,529,564.", "caveat": "The Globe article is paywalled and the board document is a PDF the review tooling could not render; both figures were read through the search index of the same documents and are consistent with each other.", "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-307be9b08afc2da9", "field": "snippet", "text": "Phase 1, the alerts, was due in spring 2026 and is now anticipated in summer 2026", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-1a7fc0bab3b6c3a0", "src-fe2124955e629888" ], "supportNote": "NBC10 Boston in October 2025: 'Phase one of the system will be complete next spring.' The MBTA's own January 2026 update: 'Following a testing and data collection period over the next several months, the MBTA anticipates Phase 1 of GLTPS will be operational in summer 2026.'", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-82ce992ddba7a78e", "field": "snippet", "text": "Automatic braking is due 2028", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-f5be84309de633c9", "src-1a7fc0bab3b6c3a0" ], "supportNote": "CommonWealth Beacon reports that Phase 2 — automatic speed control and braking — is not anticipated on trains until 2028; NBC10 Boston reports the same end date for full operation.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-22444730a002d817", "field": "lesson", "text": "The NTSB recommends and cannot compel; the FTA, a different agency, is the one that issued binding directives to the MBTA in 2022", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-d517875621c3c93e", "src-79e41a0412cafd14" ], "supportNote": "Recommendation R-09-008 was addressed to the FTA rather than to the MBTA. The FTA's own page records a separate action: a Safety Management Inspection of the MBTA between 14 April and 30 June 2022, reported on 31 August 2022 with 20 findings and four Special Directives to the MBTA.", "caveat": "The FTA's 2022 directives are a separate action and did not create this project.", "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-6868524aa4eb9d5e", "field": "lesson", "text": "Seventeen years after the NTSB asked for collision avoidance on the Green Line, no train is protected by it yet", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-7477ca779cc560e1", "src-4d46ce4f1e748195", "src-ea4bd5c1a5b6a988" ], "supportNote": "The most recent collision of the type the system is meant to stop happened on 9 February 2025 at East Somerville: a train passed a red signal at about 32 mph and struck a stationary train, injuring six people. On the 2021 Commonwealth Avenue collision the NTSB stated that 'had such a system been in place at the time of the accident, this collision would have been prevented'. The operator's page still describes alerts only.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } } ], "sources": [ { "id": "src-ea4bd5c1a5b6a988", "title": "MBTA — Green Line Train Protection System (operator project page)", "url": "https://www.mbta.com/projects/green-line-train-protection-system", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-55f11bbd7f6cccc3", "clm-be6687f16b65ee7d", "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Authoritative description of what the system does and does not do: 'The system continuously monitors train speed and location and alerts operators if a train is moving too fast or getting too close to another train.' Phase 1 'adds audible and visual alarms to alert operators about speed violations and avoid collisions'; Phase 2 'adds additional protections to help prevent passing stop signals and support safe operation in temporary slow zones'. The operator never claims the driver is replaced. Also the source for the fitting count: 'So far, 20 trains have been equipped with the new technology.' A living page that carries no date of its own, hence no publication date here.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-fe2124955e629888", "title": "MBTA — Essential work across the subway and commuter rail system in 2025 (operator, 16 January 2026)", "url": "https://www.mbta.com/news/2026-01-16/mbta-accomplished-essential-work-across-the-subway-and-commuter-rail-system-2025", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-307be9b08afc2da9" ], "temporal": { "publishedAt": "2026-01-16", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Sentence-level source for build progress and schedule: 'More than 930 GLTPS anchors installed', 'nearly 68,000 feet of messenger wire installed', 'more than 200,000 feet of cable have been installed within the track area', and 'more than 330 additional anchors along the B, C, and E branches in spring 2026'. Scope covers the signalized branches from North Station to Medford/Tufts and Union Square, the core tunnel from all branch portals to North Station, and the D branch from Riverside to Fenway — which establishes that the Green Line Extension is included. Schedule: 'Following a testing and data collection period over the next several months, the MBTA anticipates Phase 1 of GLTPS will be operational in summer 2026.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-50176f4d09eecf48", "title": "MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)", "url": "https://cdn.mbta.com/sites/default/files/2025-02/5.%20GLTPS-2%20Staff%20Summary%20Presentation%202-24-2025%20FINAL_2PM.pdf", "publisher": { "name": null, "domain": "cdn.mbta.com", "classification": "not-classified" }, "sourceType": "pdf", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-be6687f16b65ee7d", "clm-28632db03e9f0166" ], "temporal": { "publishedAt": "2025-02-25", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Contract source: award to Piper Networks not to exceed US$112,529,564; technology described as 'Piper's Cenelec SIL-4 Ultra-Wideband positioning technology to localize trains operating both at grade and in the underground central subway areas'; three deliverables — collision avoidance, overspeed protection, and full territory response to signals and speed changes. PDF; could not be rendered by the review tooling, figures verified through the search index of the same document and corroborated by the Boston Globe and CommonWealth Beacon reports listed below. Note that a SIL-4 rating is a design certification, not a result.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-d517875621c3c93e", "title": "NTSB — Collision of Two MBTA Green Line Trains, Newton, 28 May 2008 (RAR-09/02)", "url": "https://www.ntsb.gov/investigations/AccidentReports/Reports/RAR0902.pdf", "publisher": { "name": null, "domain": "ntsb.gov", "classification": "not-classified" }, "sourceType": "pdf", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-55f11bbd7f6cccc3", "clm-9e704ffb5fe8ac43", "clm-22444730a002d817" ], "temporal": { "publishedAt": "2008-05-28", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The fatal accident behind the recommendation: a westbound train travelling about 38 mph struck the rear of another near Waban, killing operator Ter'rese Edmonds. Probable cause was the operator's failure to comply with the controlling signal indication, consistent with an episode of micro-sleep; 'contributing to the accident was the lack of a positive train control system that would have intervened to stop the train and prevent the collision.' Source for the precise defect: Green Line trains 'do not incorporate systems such as trip stops (mechanical arms or electrical inductors that slow or stop a train if the operator fails to respond)'. Recommendation R-09-008 was addressed to the Federal Transit Administration, not to the MBTA — the NTSB recommends, it does not order.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-4d46ce4f1e748195", "title": "WBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023)", "url": "https://www.wbur.org/news/2023/01/05/green-line-collision-final-report", "publisher": { "name": null, "domain": "wbur.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": "2023-01-05", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Carries the NTSB's finding on the 30 July 2021 Commonwealth Avenue collision in the Board's own words: 'Had such a system been in place at the time of the accident, this collision would have been prevented.' Probable cause was the operator's sudden acceleration and 'loss of situational awareness'; 24 passengers and three MBTA workers were taken to hospital. Also records the MBTA target current at that date — completion by June 2025, itself a two-year slip.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7477ca779cc560e1", "title": "NTSB — Collision at East Somerville station, 9 February 2025 (investigation RD25FR007)", "url": "https://www.ntsb.gov/investigations/Pages/RD25FR007.aspx", "publisher": { "name": null, "domain": "ntsb.gov", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": "2025-02-09", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The most recent accident of exactly the type the system is meant to stop, on the newest section of line: at about 12:22 a.m. a train travelling about 32 mph entered a 25 mph zone, passed a red signal and entered the 10 mph station zone before striking a stationary out-of-service train. Six people were injured and the MBTA estimated US$6.6 million in damage. Preliminary report published 6 March 2025. It happened seventeen days before the board approved the Piper contract.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-efee7255e5b08ab7", "title": "Boston Globe — MBTA scraps Green Line crash prevention contract, will start over (7 June 2024)", "url": "https://www.bostonglobe.com/2024/06/07/metro/green-line-crash-prevention-tech/", "publisher": { "name": null, "domain": "bostonglobe.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-28632db03e9f0166" ], "temporal": { "publishedAt": "2024-06-07", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Source for the abandoned first attempt: an US$83M contract awarded in 2019 to the German firm BBR, later acquired by Stadler, on which the MBTA had paid about US$18M without seeing meaningful progress; the agency terminated it in June 2024 and moved to recoup the money. Paywalled; the figures were verified through the search index of the same article and are consistent with the February 2025 board procurement.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-f5be84309de633c9", "title": "CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech", "url": "https://commonwealthbeacon.org/transportation/green-line-anti-collision-system-sees-real-tangible-progress-despite-slight-delay/", "publisher": { "name": null, "domain": "commonwealthbeacon.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-82ce992ddba7a78e" ], "temporal": { "publishedAt": "2025-12-03", "updatedAt": "2025-12-05", "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Independent reporting that keeps the two phases apart: Phase 1 gives 'audible and visual alerts if the system detects a collision risk', Phase 2 adds automatic speed control and braking and is not anticipated on trains until 2028. Also the source for the slip — officials first said Phase 1 would be complete by December 2025 and then moved it to mid-2026, against a contract deadline with Piper of March 2027.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-79e41a0412cafd14", "title": "Federal Transit Administration — Special Directive 22-12 and the MBTA Safety Management Inspection", "url": "https://www.transit.dot.gov/regulations-and-programs/safety/fta-special-directive-22-12", "publisher": { "name": null, "domain": "transit.dot.gov", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-22444730a002d817" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Included so the two federal bodies are not conflated. The FTA — which can compel, unlike the NTSB — conducted its Safety Management Inspection of the MBTA between 14 April and 30 June 2022 and released the report on 31 August 2022 with 20 findings, accompanied by four Special Directives to the MBTA and one to the Massachusetts Department of Public Utilities. That is a separate action from the NTSB's 2009 recommendation and did not create this project.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7dd56ec72e8e3144", "title": "MBTA — Track Improvement Program (operator)", "url": "https://www.mbta.com/projects/track-improvement-program", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Context for the wider safety crisis this project sits inside, kept to one dated figure: the programme removed more than 220 speed restrictions and replaced more than 250,000 feet of rail, clearing the last track-related slow zones in December 2024 after 23 planned closures across four lines during that year. Operator-reported; used for scale only, not as an impact figure for the train protection system.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-1a7fc0bab3b6c3a0", "title": "NBC10 Boston — Here’s an exclusive look at the MBTA’s new train protection system on the Green Line (8 October 2025)", "url": "https://www.nbcboston.com/news/local/mbta-green-line-new-train-protection-system-exclusive-look/3820706/", "publisher": { "name": null, "domain": "nbcboston.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-be6687f16b65ee7d", "clm-307be9b08afc2da9", "clm-82ce992ddba7a78e" ], "temporal": { "publishedAt": "2025-10-08", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-29", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Ride-along with the MBTA's chief operating officer, Ryan Coholan. Describes the on-board hardware — sensors on the front, back and roof of each train talking to trackside anchors, and a cab display — and states the intended end behaviour in plain words: 'If the operator doesn't take any action the system will apply the brakes and stop the train itself.' Also the schedule as it stood in October 2025: 'Phase one of the system will be complete next spring and the entire GLTPS will be fully operational by 2028' — the spring 2026 date the MBTA's own January 2026 update then moved to summer 2026.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } } ], "coverage": { "claimsTotal": 8, "claimsMapped": 8, "sourcesTotal": 11, "sourcesUsedByClaims": 10, "sourcesWithPublicationDate": 8, "sourcesWithArchive": 0, "sourcesWithExactLocator": 0, "sourcesWithContentHash": 0 }, "limits": [ "Publisher names and source languages have not yet been classified; domains are recorded without guessing.", "Existing source notes are descriptive locators, not page- or paragraph-exact citations.", "A missing archive, publication date or content hash is shown as null rather than inferred.", "The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim." ] } }, { "id": "2026-08-27-correction-run", "createdAt": "2026-08-27T12:48:00Z", "effectiveAt": "2026-08-27", "changeType": "correction", "summary": "Re-read the board paper and the operator page in full. Removed an invented 'Cenelec SIL-4' attribution, added the contractual Phase 1 date of March 2027 and the total project budget, replaced two dead sources and dated the rest.", "preparedBy": { "type": "automation", "label": "AI-assisted evidence preparation", "humanApproved": false }, "review": { "status": "unreviewed", "by": null, "date": null, "note": "Awaiting operator and domain-expert review; publication of this revision implies neither." }, "changes": [ { "operation": "replace", "path": "/snapshot/projectFingerprint", "summary": "Updated projectFingerprint to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/governance", "summary": "Updated governance to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/claims", "summary": "Updated claims to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/sources", "summary": "Updated sources to the current sourced project record." } ], "snapshotHash": "sha256:9e703f7597fb97b98f078fd6e0e00965a93f693c9bca6a3a1f02b713b0b2bf95", "snapshot": { "asOf": "2026-08-27", "projectFingerprint": "sha256:c5d154a6d2790bd37fb3d68d51f93e7abf646d635dede614d62552f1dd81a68d", "assurance": { "status": "unreviewed", "scope": "evidence-passport-revision", "statement": "AI-assisted structural preparation. 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the general manager's November 2025 report moved it to mid-2026, and the MBTA notes the contract itself only requires Phase 1 by March 2027", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-50176f4d09eecf48", "src-f5be84309de633c9" ], "supportNote": "The board paper's phase table reads 'Phase 1 … Complete: December 2025'; CommonWealth Beacon reports the 20 November 2025 GM presentation sliding it to mid-2026 and the MBTA's answer that 'the contract with equipment manufacturer Piper calls for the first phase to be done by March 2027'.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-e63a778335d3e1f8", "field": "snippet", "text": "Phase 2, which slows or stops a train that ignores the warnings, is contracted to complete in June 2028", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-50176f4d09eecf48", "src-f5be84309de633c9" ], "supportNote": "The board paper describes Phase 2 as an avoidance system that 'Automatically slows or stops trains if warnings ignored' with 'Complete: June 2028'; CommonWealth Beacon reports Phase 2 is not anticipated on trains until 2028.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-8a9fb94a4791298a", "field": "lesson", "text": "The NTSB recommends and cannot compel; separate federal attention from the Federal Transit Administration in 2022 is what produced corrective action orders", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-d517875621c3c93e", "src-4d46ce4f1e748195" ], "supportNote": "The NTSB issues safety recommendations; WBUR reports that the MBTA's problems 'drew separate federal attention this year with a blistering Federal Transit Administration investigation that prompted multiple corrective action orders'.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-6868524aa4eb9d5e", "field": "lesson", "text": "Seventeen years after the NTSB asked for collision avoidance on the Green Line, no train is protected by it yet", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-9591ba7eaa0694c1", "src-4d46ce4f1e748195", "src-ea4bd5c1a5b6a988" ], "supportNote": "The February 2025 East Somerville collision is the same failure mode on the newest section of line — 'passed a red (stop) signal'; the NTSB found of the 2021 collision that 'Had such a system been in place at the time of the accident, this collision would have been prevented'; the operator page still describes the alerts as being introduced.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-64c2797860fa4623", "field": "lesson", "text": "the deadlines that slipped were the general manager's ambition, while the contractual one is two years later and has not moved", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-f5be84309de633c9" ], "supportNote": "The MBTA's own answer to the slip: the contract requires Phase 1 by March 2027 and 'the earlier dates mentioned publicly instead represented Eng's preference'.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } } ], "sources": [ { "id": "src-ea4bd5c1a5b6a988", "title": "MBTA — Green Line Train Protection System (operator project page)", "url": "https://www.mbta.com/projects/green-line-train-protection-system", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-55f11bbd7f6cccc3", "clm-a00c972645a0e9d6", "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Authoritative description of what the system does and does not do: 'The system continuously monitors train speed and location and alerts operators if a train is moving too fast or getting too close to another train.' Phase 1 'adds audible and visual alarms to alert operators about speed violations and avoid collisions'; Phase 2 'adds additional protections to help prevent passing stop signals and support safe operation in temporary slow zones'. The operator never claims the driver is replaced. Also the source for the fitting count: 'So far, 20 trains have been equipped with the new technology.' A living page that carries no date of its own, hence no publication date here.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-fe2124955e629888", "title": "MBTA — Essential work across the subway and commuter rail system in 2025 (operator, 16 January 2026)", "url": "https://www.mbta.com/news/2026-01-16/mbta-accomplished-essential-work-across-the-subway-and-commuter-rail-system-2025", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": "2026-01-16", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Sentence-level source for build progress and schedule: 'More than 930 GLTPS anchors installed', 'nearly 68,000 feet of messenger wire installed', 'more than 200,000 feet of cable have been installed within the track area', and 'more than 330 additional anchors along the B, C, and E branches in spring 2026'. Scope covers the signalized branches from North Station to Medford/Tufts and Union Square, the core tunnel from all branch portals to North Station, and the D branch from Riverside to Fenway — which establishes that the Green Line Extension is included. Schedule: 'Following a testing and data collection period over the next several months, the MBTA anticipates Phase 1 of GLTPS will be operational in summer 2026.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-50176f4d09eecf48", "title": "MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)", "url": "https://cdn.mbta.com/sites/default/files/2025-02/5.%20GLTPS-2%20Staff%20Summary%20Presentation%202-24-2025%20FINAL_2PM.pdf", "publisher": { "name": null, "domain": "cdn.mbta.com", "classification": "not-classified" }, "sourceType": "pdf", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a00c972645a0e9d6", "clm-d311f6f7e58f4673", "clm-b6a921eac55cf130", "clm-e63a778335d3e1f8" ], "temporal": { "publishedAt": "2025-02-25", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Board paper of 25 February 2025, read in full (text extracted from the PDF). Scope: 'a stand-alone, non-vital overlay system' with three functions — stopping vehicles before a red signal, speed enforcement, and preventing train-to-train collisions. Technology: 'Piper will deploy GPS-RTK for speed and collision warnings' above ground and 'UWB (Ultra Wide Band)' underground; equipment is LiDAR, a Master Control Unit and a train positioning antenna. Phase 1 'Complete: December 2025', Phase 2 'Complete: June 2028'. 'Negotiated Price: $112,529,564' and 'a total delivered amount not to exceed $112,529,564'; total project budget $219,103,608. One bid was received, from Piper Networks.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-d517875621c3c93e", "title": "NTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008)", "url": "https://www.ntsb.gov/investigations/AccidentReports/Reports/RAR0902.pdf", "publisher": { "name": null, "domain": "ntsb.gov", "classification": "not-classified" }, "sourceType": "pdf", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-55f11bbd7f6cccc3", "clm-9e704ffb5fe8ac43", "clm-8a9fb94a4791298a" ], "temporal": { "publishedAt": "2009-07-14", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The fatal accident behind the recommendation, read in full 2026-08-27 (text extracted from the PDF). 'Adopted July 14, 2009'; the accident itself was 28 May 2008. A westbound train 'traveling about 38 mph, struck the rear of' a stopped train; the striking operator was killed and total damage was about $8.6 million.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-4d46ce4f1e748195", "title": "WBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023)", "url": "https://www.wbur.org/news/2023/01/05/green-line-collision-final-report", "publisher": { "name": null, "domain": "wbur.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-8a9fb94a4791298a", "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": "2023-01-05", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Carries the NTSB's finding on the 30 July 2021 Commonwealth Avenue collision in the Board's own words: 'Had such a system been in place at the time of the accident, this collision would have been prevented.' Read in full 2026-08-27; it is also the source for the separation of the two federal roles — 'The MBTA's glaring safety problems drew separate federal attention this year with a blistering Federal Transit Administration investigation that prompted multiple corrective action orders', against recommendations the NTSB made 'more than a decade ago'.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-efee7255e5b08ab7", "title": "Boston Globe — MBTA scraps Green Line crash prevention contract, will start over (7 June 2024)", "url": "https://www.bostonglobe.com/2024/06/07/metro/green-line-crash-prevention-tech/", "publisher": { "name": null, "domain": "bostonglobe.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": "2024-06-07", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Paywalled and not archived; not read here. It is the report CommonWealth Beacon links to for the scrapping of the BBR contract, and is listed for that provenance only. No claim on this entry rests on it, and no figure is taken from it.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-f5be84309de633c9", "title": "CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech", "url": "https://commonwealthbeacon.org/transportation/green-line-anti-collision-system-sees-real-tangible-progress-despite-slight-delay/", "publisher": { "name": null, "domain": "commonwealthbeacon.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-9e704ffb5fe8ac43", "clm-d311f6f7e58f4673", "clm-b6a921eac55cf130", "clm-e63a778335d3e1f8", "clm-64c2797860fa4623" ], "temporal": { "publishedAt": "2025-12-03", "updatedAt": "2025-12-05", "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Independent reporting, read in full. Keeps the phases apart and carries the contractual dates the operator's own announcements do not: 'The T contracted with German firm BBR in 2019; five years later, after Eng took the helm as general manager, the agency scrapped the deal and reset the project'; 'In February, the MBTA's board of directors approved a new $112 million contract with Piper'; 'the contract with equipment manufacturer Piper calls for the first phase to be done by March 2027, and… the earlier dates mentioned publicly instead represented Eng's preference'; and the 20 November 2025 GM report sliding Phase 1 to mid-2026.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7dd56ec72e8e3144", "title": "MBTA — Track Improvement Program (operator)", "url": "https://www.mbta.com/projects/track-improvement-program", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Context for the wider safety crisis this project sits inside, read 2026-08-27. A rolling programme page that carries no publication date of its own, only dated updates — the completion of the programme is announced there on 23 December 2024. Hence date: null.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-1a7fc0bab3b6c3a0", "title": "NBC10 Boston — Here’s an exclusive look at the MBTA’s new train protection system on the Green Line (8 October 2025)", "url": "https://www.nbcboston.com/news/local/mbta-green-line-new-train-protection-system-exclusive-look/3820706/", "publisher": { "name": null, "domain": "nbcboston.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a00c972645a0e9d6" ], "temporal": { "publishedAt": "2025-10-08", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Ride-along with the MBTA's chief operating officer, Ryan Coholan. Describes the on-board hardware — sensors on the front, back and roof of each train talking to trackside anchors, and a cab display — and states the intended end behaviour in plain words: 'If the operator doesn't take any action the system will apply the brakes and stop the train itself.' Also the schedule as it stood in October 2025: 'Phase one of the system will be complete next spring and the entire GLTPS will be fully operational by 2028' — the spring 2026 date the MBTA's own January 2026 update then moved to summer 2026.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-9591ba7eaa0694c1", "title": "WBUR / State House News Service — NTSB: Green Line trolley went through stop sign before crash (6 March 2025)", "url": "https://www.wbur.org/news/2025/03/06/mbta-boston-subway-crash-green-line", "publisher": { "name": null, "domain": "wbur.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": "2025-03-06", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Read in full 2026-08-27; by Colin A. Young, State House News Service. Replaces the NTSB's own investigation page for the East Somerville collision, which now answers 'Page not found'. Quotes the preliminary report directly: 'A preliminary review of event recorder and signal data indicates the striking train was traveling about 32 mph when it entered a 25-mph zone, passed a red (stop) signal and entered the 10-mph zone in the station where it collided with the stationary out-of-service train.' 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the general manager's November 2025 report moved it to mid-2026, and the MBTA notes the contract itself only requires Phase 1 by March 2027", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-50176f4d09eecf48", "src-f5be84309de633c9" ], "supportNote": "The board paper's phase table reads 'Phase 1 … Complete: December 2025'; CommonWealth Beacon reports the 20 November 2025 GM presentation sliding it to mid-2026 and the MBTA's answer that 'the contract with equipment manufacturer Piper calls for the first phase to be done by March 2027'.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-e63a778335d3e1f8", "field": "snippet", "text": "Phase 2, which slows or stops a train that ignores the warnings, is contracted to complete in June 2028", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-50176f4d09eecf48", "src-f5be84309de633c9" ], "supportNote": "The board paper describes Phase 2 as an avoidance system that 'Automatically slows or stops trains if warnings ignored' with 'Complete: June 2028'; CommonWealth Beacon reports Phase 2 is not anticipated on trains until 2028.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-8a9fb94a4791298a", "field": "lesson", "text": "The NTSB recommends and cannot compel; separate federal attention from the Federal Transit Administration in 2022 is what produced corrective action orders", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-d517875621c3c93e", "src-4d46ce4f1e748195" ], "supportNote": "The NTSB issues safety recommendations; WBUR reports that the MBTA's problems 'drew separate federal attention this year with a blistering Federal Transit Administration investigation that prompted multiple corrective action orders'.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-6868524aa4eb9d5e", "field": "lesson", "text": "Seventeen years after the NTSB asked for collision avoidance on the Green Line, no train is protected by it yet", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-9591ba7eaa0694c1", "src-4d46ce4f1e748195", "src-ea4bd5c1a5b6a988" ], "supportNote": "The February 2025 East Somerville collision is the same failure mode on the newest section of line — 'passed a red (stop) signal'; the NTSB found of the 2021 collision that 'Had such a system been in place at the time of the accident, this collision would have been prevented'; the operator page still describes the alerts as being introduced.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-64c2797860fa4623", "field": "lesson", "text": "the deadlines that slipped were the general manager's ambition, while the contractual one is two years later and has not moved", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-f5be84309de633c9" ], "supportNote": "The MBTA's own answer to the slip: the contract requires Phase 1 by March 2027 and 'the earlier dates mentioned publicly instead represented Eng's preference'.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } } ], "sources": [ { "id": "src-ea4bd5c1a5b6a988", "title": "MBTA — Green Line Train Protection System (operator project page)", "url": "https://www.mbta.com/projects/green-line-train-protection-system", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-55f11bbd7f6cccc3", "clm-a00c972645a0e9d6", "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Authoritative description of what the system does and does not do: 'The system continuously monitors train speed and location and alerts operators if a train is moving too fast or getting too close to another train.' Phase 1 'adds audible and visual alarms to alert operators about speed violations and avoid collisions'; Phase 2 'adds additional protections to help prevent passing stop signals and support safe operation in temporary slow zones'. The operator never claims the driver is replaced. Also the source for the fitting count: 'So far, 20 trains have been equipped with the new technology.' A living page that carries no date of its own, hence no publication date here.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-fe2124955e629888", "title": "MBTA — Essential work across the subway and commuter rail system in 2025 (operator, 16 January 2026)", "url": "https://www.mbta.com/news/2026-01-16/mbta-accomplished-essential-work-across-the-subway-and-commuter-rail-system-2025", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": "2026-01-16", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Sentence-level source for build progress and schedule: 'More than 930 GLTPS anchors installed', 'nearly 68,000 feet of messenger wire installed', 'more than 200,000 feet of cable have been installed within the track area', and 'more than 330 additional anchors along the B, C, and E branches in spring 2026'. Scope covers the signalized branches from North Station to Medford/Tufts and Union Square, the core tunnel from all branch portals to North Station, and the D branch from Riverside to Fenway — which establishes that the Green Line Extension is included. Schedule: 'Following a testing and data collection period over the next several months, the MBTA anticipates Phase 1 of GLTPS will be operational in summer 2026.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-50176f4d09eecf48", "title": "MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)", "url": "https://cdn.mbta.com/sites/default/files/2025-02/5.%20GLTPS-2%20Staff%20Summary%20Presentation%202-24-2025%20FINAL_2PM.pdf", "publisher": { "name": null, "domain": "cdn.mbta.com", "classification": "not-classified" }, "sourceType": "pdf", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a00c972645a0e9d6", "clm-d311f6f7e58f4673", "clm-b6a921eac55cf130", "clm-e63a778335d3e1f8" ], "temporal": { "publishedAt": "2025-02-25", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Board paper of 25 February 2025, read in full (text extracted from the PDF). Scope: 'a stand-alone, non-vital overlay system' with three functions — stopping vehicles before a red signal, speed enforcement, and preventing train-to-train collisions. Technology: 'Piper will deploy GPS-RTK for speed and collision warnings' above ground and 'UWB (Ultra Wide Band)' underground; equipment is LiDAR, a Master Control Unit and a train positioning antenna. Phase 1 'Complete: December 2025', Phase 2 'Complete: June 2028'. 'Negotiated Price: $112,529,564' and 'a total delivered amount not to exceed $112,529,564'; total project budget $219,103,608. One bid was received, from Piper Networks.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-d517875621c3c93e", "title": "NTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008)", "url": "https://www.ntsb.gov/investigations/AccidentReports/Reports/RAR0902.pdf", "publisher": { "name": null, "domain": "ntsb.gov", "classification": "not-classified" }, "sourceType": "pdf", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-55f11bbd7f6cccc3", "clm-9e704ffb5fe8ac43", "clm-8a9fb94a4791298a" ], "temporal": { "publishedAt": "2009-07-14", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The fatal accident behind the recommendation, read in full 2026-08-27 (text extracted from the PDF). 'Adopted July 14, 2009'; the accident itself was 28 May 2008. A westbound train 'traveling about 38 mph, struck the rear of' a stopped train; the striking operator was killed and total damage was about $8.6 million.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-4d46ce4f1e748195", "title": "WBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023)", "url": "https://www.wbur.org/news/2023/01/05/green-line-collision-final-report", "publisher": { "name": null, "domain": "wbur.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-8a9fb94a4791298a", "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": "2023-01-05", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Carries the NTSB's finding on the 30 July 2021 Commonwealth Avenue collision in the Board's own words: 'Had such a system been in place at the time of the accident, this collision would have been prevented.' Read in full 2026-08-27; it is also the source for the separation of the two federal roles — 'The MBTA's glaring safety problems drew separate federal attention this year with a blistering Federal Transit Administration investigation that prompted multiple corrective action orders', against recommendations the NTSB made 'more than a decade ago'.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-efee7255e5b08ab7", "title": "Boston Globe — MBTA scraps Green Line crash prevention contract, will start over (7 June 2024)", "url": "https://www.bostonglobe.com/2024/06/07/metro/green-line-crash-prevention-tech/", "publisher": { "name": null, "domain": "bostonglobe.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": "2024-06-07", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Boston Globe report of 7 June 2024 under the headline 'T scraps Green Line crash-prevention contract recommended by NTSB in 2009'. It is the report CommonWealth Beacon links to for the scrapping of the contract, and is listed for that provenance; no figure on this entry is taken from it.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-f5be84309de633c9", "title": "CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech", "url": "https://commonwealthbeacon.org/transportation/green-line-anti-collision-system-sees-real-tangible-progress-despite-slight-delay/", "publisher": { "name": null, "domain": "commonwealthbeacon.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-9e704ffb5fe8ac43", "clm-d311f6f7e58f4673", "clm-b6a921eac55cf130", "clm-e63a778335d3e1f8", "clm-64c2797860fa4623" ], "temporal": { "publishedAt": "2025-12-03", "updatedAt": "2025-12-05", "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Independent reporting, read in full. Keeps the phases apart and carries the contractual dates the operator's own announcements do not: 'The T contracted with German firm BBR in 2019; five years later, after Eng took the helm as general manager, the agency scrapped the deal and reset the project'; 'In February, the MBTA's board of directors approved a new $112 million contract with Piper'; 'the contract with equipment manufacturer Piper calls for the first phase to be done by March 2027, and… the earlier dates mentioned publicly instead represented Eng's preference'; and the 20 November 2025 GM report sliding Phase 1 to mid-2026.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7dd56ec72e8e3144", "title": "MBTA — Track Improvement Program (operator)", "url": "https://www.mbta.com/projects/track-improvement-program", "publisher": { "name": null, "domain": "mbta.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Context for the wider safety crisis this project sits inside, read 2026-08-27. A rolling programme page that carries no publication date of its own, only dated updates — the completion of the programme is announced there on 23 December 2024. Hence date: null.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-1a7fc0bab3b6c3a0", "title": "NBC10 Boston — Here’s an exclusive look at the MBTA’s new train protection system on the Green Line (8 October 2025)", "url": "https://www.nbcboston.com/news/local/mbta-green-line-new-train-protection-system-exclusive-look/3820706/", "publisher": { "name": null, "domain": "nbcboston.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a00c972645a0e9d6" ], "temporal": { "publishedAt": "2025-10-08", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Ride-along with the MBTA's chief operating officer, Ryan Coholan. Describes the on-board hardware — sensors on the front, back and roof of each train talking to trackside anchors, and a cab display — and states the intended end behaviour in plain words: 'If the operator doesn't take any action the system will apply the brakes and stop the train itself.' Also the schedule as it stood in October 2025: 'Phase one of the system will be complete next spring and the entire GLTPS will be fully operational by 2028' — the spring 2026 date the MBTA's own January 2026 update then moved to summer 2026.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-9591ba7eaa0694c1", "title": "WBUR / State House News Service — NTSB: Green Line trolley went through stop sign before crash (6 March 2025)", "url": "https://www.wbur.org/news/2025/03/06/mbta-boston-subway-crash-green-line", "publisher": { "name": null, "domain": "wbur.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-6868524aa4eb9d5e" ], "temporal": { "publishedAt": "2025-03-06", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Read in full 2026-08-27; by Colin A. Young, State House News Service. Replaces the NTSB's own investigation page for the East Somerville collision, which now answers 'Page not found'. Quotes the preliminary report directly: 'A preliminary review of event recorder and signal data indicates the striking train was traveling about 32 mph when it entered a 25-mph zone, passed a red (stop) signal and entered the 10-mph zone in the station where it collided with the stationary out-of-service train.' Two passengers and four crew were hurt; the MBTA put damage at about $6.6 million.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } } ], "coverage": { "claimsTotal": 9, "claimsMapped": 9, "sourcesTotal": 10, "sourcesUsedByClaims": 7, "sourcesWithPublicationDate": 8, "sourcesWithArchive": 0, "sourcesWithExactLocator": 0, "sourcesWithContentHash": 0 }, "limits": [ "Publisher names and source languages have not yet been classified; domains are recorded without guessing.", "Existing source notes are descriptive locators, not page- or paragraph-exact citations.", "A missing archive, publication date or content hash is shown as null rather than inferred.", "The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim." ] } } ] }