BOSTON — The National Transportation Safety Board will investigate after one Massachusetts Bay Transportation Authority light rail train rear-ended another Friday, July 30, injuring 25, including operators on both vehicles.
The Boston Globe reports the accident occurred on the Green Line B Branch, on Commonwealth Avenue in front of the Boston University campus. The injured were taken to local hospitals after a westbound train struck the train in front of it, damaging the vehicles and the rail line. One operator, who was not identified, was placed on paid administrative leave while the accident is investigated. In addition to the MBTA and NTSB, the Suffolk district attorney’s office is also investigating.
The accident comes 13 years after a fatal Green Line crash that the NTSB said could have been prevented by a positive train control-type system and called for the installation of such technology. That work is still estimated to be three years from completion, the Globe reports.
Back 100 years ago there was a system that tripped the brakes if a railcar passed a stop-signal.
It was a mechanical device that mounted on the truck. There was a corresponding T-shaped device with a counterweight on the tie that was held down by an electromagnet when the signal was not “stop” and the train was not protected by another stop-signal behind it. (otherwise the trip would stop the second car of a train but it would fail safe).
The Hudson & Manhattan tubes and Philadelphia’s Market St Elevated used this system.
I don’t know that PTC is compatible with trains that run nose – to – tail under Visual Flight Rules. AEB (automatic emergency braking) is found on most news automobiles – maybe that’s what MBTA is actually developing.
If I had several billion dollars to play with there’s a whole lot of improvements the Green Line needs. It’s the most crush-loaded system imaginable (or at least was, prior to COVID). Full trains don’t even stop for more passengers, and it’s impossible to swipe a fare card with people squeezed in like sardines with no room to stand tippy-toe.