1001 Smart Cities
🇺🇸 Boston

Green Line Train Protection System

🤖 AI-generated summary · ◆ 9 sourced claims · 🔎 Last verified

This overview was generated with AI from the public sources listed below and checked against them before publication. It has not had a complete human fact-check — treat it as a starting point and follow the sources.

9 sourced claims on this page, none individually verified yet — turn on “Sources in the text” to see each one.

How this atlas is made · What “last verified” means · What “source-checked” means · The full record behind this page

✎ Corrected 27 Aug 2026 Record revised. · 2 revisions in all What changed →

The NTSB recommended collision avoidance here in 2009. Seventeen years on, no train is protected by it: the first contract was scrapped, a replacement was let in 2025, and braking is contracted for June 2028.

Outcome🔄 Ongoing
Evidence📊 Independentgrades the sourcing — this entry states no impact figure
what does this mean?The strongest source is an independent non-academic evaluation: an audit office, a government or EU review, or an NGO. It grades who did the looking — not how well the project went. All four grades →
Run byMassachusetts Bay Transportation Authority (MBTA)
Scale🗺️ Regional
CostUS$112,529,564 Piper Networks contract approved February 2025, inside a total project budget of US$219,103,608; a 2019 contract with the German firm BBR was scrapped in 2024
FundingMBTA capital programme

Part of 1001 Smart Cities — 1,167 documented projects · 🏙️ 9 more in Boston · 🚌 Public transport guide · 🚲 Mobility projects

Boston's Green Line light rail has no system that enforces its signals or speed limits — operators simply obey them. The MBTA is fitting a Piper Networks overlay that uses GPS-RTK above ground and ultra-wideband positioning in the tunnels to warn of overspeed and closing trains; the operator says 20 trains have been equipped so far. The NTSB recommended collision avoidance in 2009; a 2019 contract with the German firm BBR was scrapped in 2024 and re-let to Piper Networks in February 2025 for $112,529,564, inside a total project budget of $219,103,608. The board paper gave Phase 1, the alerts, a December 2025 completion date; 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. Phase 2, which slows or stops a train that ignores the warnings, is contracted to complete in June 2028.

In build 📅 since 2019

🎓 Lesson

A safety recommendation is not an order. The NTSB recommends and cannot compel; separate federal attention from the Federal Transit Administration in 2022 is what produced corrective action orders. Seventeen years after the NTSB asked for collision avoidance on the Green Line, no train is protected by it yet. And the dates the public hears are not the dates anyone owes: the deadlines that slipped were the general manager's ambition, while the contractual one is two years later and has not moved.

🚲 MobilityPublic transportSafety & securitySensors & IoT

Sources

↗ MBTA — Green Line Train Protection System (operator project page)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.
↗ MBTA — Essential work across the subway and commuter rail system in 2025 (operator, 16 January 2026)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.'
↗ MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)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.
↗ NTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008)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.
↗ WBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023)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'.
Show 5 more sourcesShow fewer
↗ Boston Globe — MBTA scraps Green Line crash prevention contract, will start over (7 June 2024)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.
↗ CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision techPublished 3 December 2025 · updated 5 December 2025Independent 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.
↗ MBTA — Track Improvement Program (operator)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.
↗ NBC10 Boston — Here’s an exclusive look at the MBTA’s new train protection system on the Green Line (8 October 2025)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.
↗ WBUR / State House News Service — NTSB: Green Line trolley went through stop sign before crash (6 March 2025)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.

📅 How old is the evidence?

Two clocks, kept apart: when this entry’s sources were published, and what has happened to its record in the atlas. Documented span: since 2019. 8 of 10 sources carry a publication date, from 14 July 2009 to 16 January 2026.

When the sources were published

  1. National Transportation Safety Board (NTSB) · oversight bodyNTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008)
  2. WBUR · pressWBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023)
  3. The Boston Globe · pressBoston Globe — MBTA scraps Green Line crash prevention contract, will start over (7 June 2024)
  4. Massachusetts Bay Transportation Authority (MBTA) · operatorMBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)
  5. WBUR · pressWBUR / State House News Service — NTSB: Green Line trolley went through stop sign before crash (6 March 2025)
  6. NBC10 Boston · pressNBC10 Boston — Here’s an exclusive look at the MBTA’s new train protection system on the Green Line (8 October 2025)
  7. CommonWealth Beacon · pressCommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech · updated 5 December 2025
  8. Massachusetts Bay Transportation Authority (MBTA) · operatorMBTA — Essential work across the subway and commuter rail system in 2025 (operator, 16 January 2026)

Every source, with links ↑

What happened to this record

  1. Record revised
  2. 1 source added
  3. Entered the record
  4. Sources last read

Every revision, permanent →

Show your work What this page rests on and what it can’t tell you · all 9 claims with their sources · the forensic record

Evidence Passport · public beta 9 addressable claims, 10 source dossiers, one permanent baseline. The passport is unreviewed — an AI-assisted structural migration, not a human or expert endorsement. Every revision keeps a permanent copy under revision history.

Inspect the claims, one by one — verbatim text, sources and caveats for all 9

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-55f11bbd7f6cccc3 descriptive
Boston's Green Line light rail has no system that enforces its signals or speed limits — operators simply obey them
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The 2009 NTSB report on the Newton collision records that the Green Line had no train protection to stop a train that passed its controlling signal; the operator's current project page describes the system being installed as still being introduced.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. NTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008)
  2. MBTA — Green Line Train Protection System (operator project page)
Claim 2 clm-a00c972645a0e9d6 quantitative
The MBTA is fitting a Piper Networks overlay that uses GPS-RTK above ground and ultra-wideband positioning in the tunnels to warn of overspeed and closing trains; the operator says 20 trains have been equipped so far
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The board paper says 'Piper will deploy GPS-RTK for speed and collision warnings' above ground and 'UWB (Ultra Wide Band)' underground, in 'a stand-alone, non-vital overlay system'; the project page states 'So far, 20 trains have been equipped with the new technology.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)
  2. MBTA — Green Line Train Protection System (operator project page)
  3. NBC10 Boston — Here’s an exclusive look at the MBTA’s new train protection system on the Green Line (8 October 2025)
Claim 3 clm-9e704ffb5fe8ac43 quantitative
The NTSB recommended collision avoidance in 2009
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The NTSB's 2009 report on the 2008 Newton collision made the recommendation; CommonWealth Beacon dates it to 2009 as well.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. NTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008)
  2. CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech
Claim 4 clm-d311f6f7e58f4673 quantitative
a 2019 contract with the German firm BBR was scrapped in 2024 and re-let to Piper Networks in February 2025 for $112,529,564, inside a total project budget of $219,103,608
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
'The T contracted with German firm BBR in 2019; five years later… the agency scrapped the deal and reset the project'; the February 2025 board paper sets the negotiated price at $112,529,564 and the total project budget at $219,103,608.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech
  2. MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)
Claim 5 clm-b6a921eac55cf130 quantitative
The board paper gave Phase 1, the alerts, a December 2025 completion date; 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
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
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
No claim-specific caveat recorded

Sources carrying this claim

  1. MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)
  2. CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech
Claim 6 clm-e63a778335d3e1f8 quantitative
Phase 2, which slows or stops a train that ignores the warnings, is contracted to complete in June 2028
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
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
No claim-specific caveat recorded

Sources carrying this claim

  1. MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator)
  2. CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech
Claim 7 clm-8a9fb94a4791298a quantitative
The NTSB recommends and cannot compel; separate federal attention from the Federal Transit Administration in 2022 is what produced corrective action orders
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
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
No claim-specific caveat recorded

Sources carrying this claim

  1. NTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008)
  2. WBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023)
Claim 8 clm-6868524aa4eb9d5e descriptive
Seventeen years after the NTSB asked for collision avoidance on the Green Line, no train is protected by it yet
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
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
No claim-specific caveat recorded

Sources carrying this claim

  1. WBUR / State House News Service — NTSB: Green Line trolley went through stop sign before crash (6 March 2025)
  2. WBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023)
  3. MBTA — Green Line Train Protection System (operator project page)
Claim 9 clm-64c2797860fa4623 descriptive
the deadlines that slipped were the general manager's ambition, while the contractual one is two years later and has not moved
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
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
No claim-specific caveat recorded

Sources carrying this claim

  1. CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech
Forensic record — source dossiers, gaps, hashes and the exact revision this page renders

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-08-27-correction-run-2 effective 2026-08-27 · created 2026-08-27

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:e3ae488932fc2c7f91a0d09388efb970847811bc34c77df711e8bba4bd7a7abd
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
9
of 9 claims mapped
10
source dossiers
8
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Massachusetts Bay Transportation Authority (MBTA)
Actor types
utility
Funding model
public
Funding description
MBTA capital programme
Cost
US$112,529,564 Piper Networks contract approved February 2025, inside a total project budget of US$219,103,608; a 2019 contract with the German firm BBR was scrapped in 2024
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

10 source dossiers

MBTA — Green Line Train Protection System (operator project page) mbta.com · 3 linked claims

Open original source ↗

Stable source ID
src-ea4bd5c1a5b6a988
Publisher
Name not classified · mbta.com
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.

Descriptive only — not page/paragraph exact
Claims linked
MBTA — Essential work across the subway and commuter rail system in 2025 (operator, 16 January 2026) mbta.com · background

Open original source ↗

Stable source ID
src-fe2124955e629888
Publisher
Name not classified · mbta.com
Type / language
web-page · language not classified
Published
2026-01-16
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.'

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
MBTA Board of Directors — GLTPS-2 Procurement staff summary, 25 February 2025 (operator) cdn.mbta.com · 4 linked claims

Open original source ↗

Stable source ID
src-50176f4d09eecf48
Publisher
Name not classified · cdn.mbta.com
Type / language
pdf · language not classified
Published
2025-02-25
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.

Descriptive only — not page/paragraph exact
Claims linked
NTSB — RAR-09/02, adopted 14 July 2009: Collision of Two MBTA Green Line Trains, Newton (accident 28 May 2008) ntsb.gov · 3 linked claims

Open original source ↗

Stable source ID
src-d517875621c3c93e
Publisher
Name not classified · ntsb.gov
Type / language
pdf · language not classified
Published
2009-07-14
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.

Descriptive only — not page/paragraph exact
Claims linked
WBUR — In final report, feds fault driver, overdue safety features in 2021 Green Line crash (5 January 2023) wbur.org · 2 linked claims

Open original source ↗

Stable source ID
src-4d46ce4f1e748195
Publisher
Name not classified · wbur.org
Type / language
web-page · language not classified
Published
2023-01-05
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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'.

Descriptive only — not page/paragraph exact
Claims linked
Boston Globe — MBTA scraps Green Line crash prevention contract, will start over (7 June 2024) bostonglobe.com · background

Open original source ↗

Stable source ID
src-efee7255e5b08ab7
Publisher
Name not classified · bostonglobe.com
Type / language
web-page · language not classified
Published
2024-06-07
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
CommonWealth Beacon — The T will soon roll out Green Line trolleys with anti-collision tech commonwealthbeacon.org · 5 linked claims

Open original source ↗

Stable source ID
src-f5be84309de633c9
Publisher
Name not classified · commonwealthbeacon.org
Type / language
web-page · language not classified
Published
2025-12-03
Updated
2025-12-05
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.

Descriptive only — not page/paragraph exact
Claims linked
MBTA — Track Improvement Program (operator) mbta.com · background

Open original source ↗

Stable source ID
src-7dd56ec72e8e3144
Publisher
Name not classified · mbta.com
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
NBC10 Boston — Here’s an exclusive look at the MBTA’s new train protection system on the Green Line (8 October 2025) nbcboston.com · 1 linked claim

Open original source ↗

Stable source ID
src-1a7fc0bab3b6c3a0
Publisher
Name not classified · nbcboston.com
Type / language
web-page · language not classified
Published
2025-10-08
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

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.

Descriptive only — not page/paragraph exact
Claims linked
WBUR / State House News Service — NTSB: Green Line trolley went through stop sign before crash (6 March 2025) wbur.org · 1 linked claim

Open original source ↗

Stable source ID
src-9591ba7eaa0694c1
Publisher
Name not classified · wbur.org
Type / language
web-page · language not classified
Published
2025-03-06
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-27
Dossier created
2026-08-27
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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.

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Compare this project

🇺🇸 Muni Metro Advanced Train Control System & Its Replacement · San Francisco San Francisco's tunnel has driven trains since 1998 and is replacing that; Boston's Green Line still has nothing enforcing its signals. 🇺🇸 MTA Subway Communications-Based Train Control · New York City New York has been retrofitting signals line by line since 2009; Boston's Green Line is due its first alarms in 2026 and braking in 2028. 🇯🇵 Nanko Port Town Line (New Tram) Driverless Guideway · Osaka Osaka put crews back aboard after its 1993 runaway; Boston's Green Line never had automation to lose — its 2008 crash killed the operator.

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🚦 Asphalt or algorithms📖 CBTC (communications-based train control)📖 Automated speed enforcement (speed cameras)📖 Flood early-warning system
📎 Cite this project

1001 Smart Cities (2026). “Green Line Train Protection System” — Boston, United States. The Smart City Atlas. https://1001smartcities.org/projects/boston-green-line-train-protection/ (last verified 2026-08-27). Data: CC BY 4.0.

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