Off The Rails
Exploring the Curious Context and History Behind Boston’s Green Line Derailments
A visual story by Gab K De Jesus
I first came to the U.S. as an international student, landing in cozy Savannah, Georgia. On the morning of my first online class, my desk began quivering—then I started swaying in my seat. I froze, first day anxiety momentarily forgotten as I unmuted, “is there an earthquake?”
Turns out, it was a freight train passing behind my dorm building. For the next three years, I would hear its bellowing horn multiple times throughout the day—sometimes before the sun was even out. My friends would complain, but I enjoyed the chaotic symphony of its teeny bell clangs and groaning cars. We had no such shaking behemoth back home in the Philippines.
I got my first taste of rail transport after moving to Washington, D.C., where I was spoiled by the Metro’s prompt service. After, when I moved to Boston, I wasn’t exactly excited by what I had heard from friends about the Massachusetts Bay Transportation Authority (MBTA)—its Green Line specifically.
Just Another Day
A crowd milled about the tight platform. Almost as if taunting us, a “no service” train rolled past. Groans of frustration filled the underground, with some passengers power-walking to the opposite platform instead. Just another day on Boston’s green line.
Until it isn’t.
On October 1st, 2024, a green line train derailed, injuring seven of about 50 passengers. A preliminary investigation by the National Transportation Safety Board (NTSB) revealed that the driver had been going 36 mph in a 10-mph zone, running a stop signal and derailing at a moving switch (where trains change paths.)
My experience with D.C.’s Metro rail system had been carefree—the only thing I worried about was an extra 10 minute wait. Moving to Boston was the first time I was faced with the possibility of being in a derailment. How big of an issue was it?
I started exploring derailment reports filed to the Federal Railroad Administration (FRA). What I found painted a grim picture.
Why were passenger train derailments sky high on the green line? Was it something to worry about? The search for answers will take us on a ride through some interesting history. We’ll find out what was common between the 1860s and today’s Boston rails, see how the green line compares to other light rails in the US, and learn what management is doing to improve the situation.
Echoes of the Past
As the American Revolution ended, settlers started moving to the Boston Peninsula. Landfill projects and bridges to nearby towns were built to accommodate the growing population, and it wasn’t long before Boston was too big to walk.
Trolley Car on Oxford Street, New Bedford. From the Earl D. Wilson Collection. (Ca. 1850-1959)
In 1856, the first horse drawn rail car started operation, offering a smoother ride and greater speeds. By 1887, the General Court of Massachusetts passed an act consolidating the more than 20 rail companies into the West End Street Railway.
The West End Company started looking for alternatives to horses, which suffered injury and illness. Cable cars similar to San Francisco and D.C.’s were considered, but cold weather made maintenance difficult. Instead, on January 1, 1889 the West End Company began using electric streetcars, powered by overhead wires.
As the 1890s approached, Boston’s colonial-era streets struggled to accommodate growing transportation needs. Traffic was so bad that the Boston Transit Commission was created to “study remedies.” They determined that a streetcar subway was the best solution.
In 1897, Tremont Street Subway—the first subway in the United States—was completed. D.W. Rowlands notes, “[it] was a short tunnel to get cars from Boston’s large streetcar network out of downtown traffic… neither built as rapid transit nor to serve as a single coherent line.” But it did the job: Traffic was instantly eased, with a passenger comparing it to “a barrier [removed] from the channel of a clogged-up river.” (Just as instant was the first complaint of delay, four hours later.)
In 1896, the street rail, subways, and elevated rails came together under the Boston Elevated Railway Company (BERy). Then in 1947, facing declining ridership due to automobiles, BERy was absorbed by the fully publicly-owned Metropolitan Transit Authority (MTA).
After concerns that further expansion of the MTA would simply lead to more debt and congestion, the existing transport system was studied by experts and consolidated into a “combined regional transit system”—the MBTA we know today.
It gave new energy to my train rides knowing I was on routes used over the past 150 years. I feel a bit silly thinking it now, but that also meant that rail quality wasn’t quite the reason for derailments—a 2023 report showed that the MBTA has replaced 117,090 feet of Green Line track within the past few years.
Could the culprit be one other constant between the rail cars of the 1860s and today: its human operators?
Human Factors
The train emerged into the bright Boston fall. Crisp piles of leaves scattered the railside, and bright bursts of orange and yellow greeted us overhead.
I watched the operator nudge the train along, before stopping at an intersection. I peered out, expecting to see a red light. Instead, a white horizontal line glowed steadily—the Green Line’s above-ground version of a stoplight. It blinked vertical, signalling go.
So-called wayside signals aren’t just for synchronizing with vehicle traffic—they also tell an operator when the rail ahead is ready and set for their specific route.
A switch activates at Kenmore Station. A few meters away, a train waits for the go signal, else risking derailment.
While advanced railways automate trains to follow signals, the Green Line’s antiquated signal system, rail age, and shared right-of-way means human operators are likely to stay.
Right-of-Way Classifications
Why don’t cars ride over sidewalks, or people walk over train rails? Right-of-way dictates where pedestrians and vehicles can pass with legal precedence.
Exclusive Right-of-Way
Train runs on its own path. Traffic and pedestrians cannot cross in front of it.
Example: Kenmore Station
Semi-Exclusive Right-of-Way
Train is partially separated from traffic, with path shared at crossings and intersections.
Example: Longwood Station
Shared Right-of-Way
Train runs on surface streets, mixing with traffic.
Example: Heath Street
Human operators are perfectly fine—even D.C.’s Metro continues to use them. However, the Green Line sees a lot of human factor derailments: an MBTA Quarterly Safety Report cited them as “probable cause in >40% of derailments [from 1999-2018].”
As I dug deeper into the derailment reports, I found that human factors remain an issue for the Green Line:
- On January 2, 2020, a Green Line train derailed after violating a red signal
- On May 09, 2020, an operator had the route but not the signal, derailing at a switch.
- On June 21, 2020, an operator thought they were clear to proceed, only to derail at an improperly set switch.
It would be easy to point a finger at operators, but it looks like a myriad of issues magnify human error. TransitMatters, a Boston-based transit advocacy and policy group, issued a statement about the recent October derailment:
“While operator negligence appears to have been a key factor… we hope the MBTA is also examining the low-speed design of the switch where [the derailment occurred]… Additionally, this derailment highlights the urgent need for the long-overdue overhaul of the Green Line’s signal system.” —TransitMatters, October 2024
Could This Have Been Avoided?
PTC is designed to prevent accidents from human error by stopping the train before they occur, such as…
Train
Collisions
Derailments from
Overspeeding
Unauthorized Entry
into Maintenance Areas
Passing Improperly
Positioned Switches
Although PTC might alleviate human error, it performs best in exclusive right-of-way (paths not shared with other vehicles). Would the safety system help the Green Line, given its shared right-of-way? Let’s look at the data.
Of the 38 derailments on the Green Line, only 5 were on shared right-of-way (where PTC wouldn’t work well). Additionally, human error was not responsible for any of these derailments.
6 were on semi-exclusive right-of-way, separated from vehicles and pedestrians except at intersections or crossings. None of these were attributed to human error either.
The other 27 were on exclusive right-of-way—meaning operators had no traffic or pedestrians to contend with. This is where PTC would work best. 8 derailments were attributed to human error, while 19 had no factors listed.
While PTC isn’t normally installed on light rails, the Green Line doesn’t exactly have the best track record among legacy railways modernized into light rails.
In response to the NTSB’s call for PTC, the MBTA developed the Green Line Train Protection System (GLTPS). The bespoke safety system will stop the train if overspeeding, near a red light, or near another train—preventing the human factors that most contribute to derailments.
Safety, Moving Forward
“Cheers, thanks for the ride.” I waved to the operator. “Have a blessed day, brother.” He called back, before setting the train in motion again.
Despite the high count of derailments, your chances of being in one are quite low.
Even with generous estimates, there’s only a 0.00006% chance of being in a derailment in any given year. That’s 1 in 1,666,667 riders. To contrast, the annual chance of being in a car crash is 0.19%, or 1 in 526 people.
Well, that certainly puts derailments in perspective.
Even with generous estimates, there’s only a 0.00006% chance of being in a derailment in any given year.
Injuries are even rarer, since the Green Line travels at an average of 10.5 mph. Injuries—all minor—were only reported from three derailments: two were overspeeding, and one was going 28 mph.
The Green Line will likely stay human operated, but the future looks favorable for lessening derailments. Huntington Avenue/South Huntington Avenue will be redesigned so trains don’t run in mixed-right-of-way with traffic.
The project is double-purpose: stations will need to be accessible for the upcoming Type 10 trains, which will roll out around 2026. These “supercars” will replace the aging Type 7 and Type 8 fleet, and come installed with the Green Line Train Protection System, preventing incidents from human error.
While working on this story, I wondered why I felt such an affinity with the Green Line, despite its mixed reliability and ear-splitting tracks. I realized it was the community, the history, the personality of each train and its operator, the memeable unreliability that spawned an urban road race pitting runner against rail.
During my time in D.C., the Metro was functioning so well it was just that: a way to get from point A to B. In Boston, there’s a sense of pride in the tireless work put into improving the Green Line. I felt it most when I visited the Type 10 mock-up and overheard employees gushing, “Yeah, it’s great to see that everyone’s liking the train!”
It’s infectious energy; I left with a smile on my face.
Appendix
Calculating derailment vs car crash chances
Annual chance of being in a derailment
= riders in derailments / (sum of riders x 10 years)
= 3209 / (500,276,800 x 10)
= 0.00006%
Annual chance of being in a car accident
= car crashes / (sum of population x 10 years)
= 67,711,561 / (3,568,462,071 x 10)
= 0.19%
Special Thanks
Nabeel Gillani for a great stats class, invaluable discussions, and reminding me that converting to percentage means moving the decimal point.
Sarah Grace for imparting her info design experience and attention to detail. This story wouldn’t have been possible without what I learned from her during my time at CSIS.
Gina Kim for first telling me about the Green Line when I was considering moving to Boston.
D.W. Rowlands and Marco Hernandez for sharing their expertise and lighting the path forward.
Last but not least, the MBTA, and the employees going above and beyond for riders.