Why don't they cover the third rail?

Two weeks ago, a man was electrocuted at Park Street. I'm surprised that it has not been mentioned in this forum. At Park Street, the third rail is right over the edge of the platform. While the news article was not specific, I'm going to assume he simply fell. At every other T station, the third rail is opposite the platform.

If you go to New York, the third rail is covered EVERYWHERE, not just in stations. Why not in Boston, at least in Park Street. Perhaps outdoors the third rail should be covered to keep the snow off.

Park Street has a center platform as well as side platforms, so there is no way to avoid having a third rail directly adjacent to a platform.

If the trains had batteries, perhaps there would be no need to run third rails into stations.

Then there's the strange case of the Blue Line, where trains are equipped both for third rail and catenary.

The Green Line runs from catenary throughout the subway, so one has to ask why the other lines do not do so. Is it merely to save money? Or is there an operational advantage to using third rail instead of catenary?

Third rail is far more durable than catenary. Doesn't break or snag when in use, and isn't as susceptible to damage from the weight of ice.

As to why it's not covered? Dunno.... Maybe people in Boston, Chicago and London are smarter than those in NYC, because that's the only place I've ever seen it covered...

Why don't they build shutters (walls with doors, like elevator doors) so that you cannot fall into the subway pit?

BandA wrote: ↑Tue Sep 03, 2024 12:19 pm Why don't they build shutters (walls with doors, like elevator doors) so that you cannot fall into the subway pit?

The first time I ever saw those was in Leningrad (now St. Petersburg), Russia in 1975. I found myself at a metro station with no obvious tracks, but opposing walls lined with elevator doors. Before I could guess what that was about, I heard the screech of a train coming to a halt, and all the elevator doors opened on one side, each set perfect aligned with the doors on the train.

charlesriverbranch wrote: ↑Tue Sep 03, 2024 10:08 am Park Street has a center platform as well as side platforms, so there is no way to avoid having a third rail directly adjacent to a platform.

If the trains had batteries, perhaps there would be no need to run third rails into stations.

Then there's the strange case of the Blue Line, where trains are equipped both for third rail and catenary.

The Green Line runs from catenary throughout the subway, so one has to ask why the other lines do not do so. Is it merely to save money? Or is there an operational advantage to using third rail instead of catenary?

In reverse order, third rail -- besides being more durable -- is capable of carrying far more current than trolley wire, a necessity for the heavier and more power-consumptive rapid transit cars.
The Blue Line was originally a streetcar line until it got upgraded. The present overhead is more substantial than the original trolley wire.
Until battery fires are eliminated, lithium or other smoke is far more a mass-casualty threat in tunnels than the third rail.
Combining the first item with other responses, materials that are nonconductive and could be used to provide protection from the third rail also tend to produce smoke or outgassing when heated, another hazard in tunnels. YouTube has a video of a Red Line derailment on the surface that produced high-temperature arcing.

It's true that Boston is one of the few rapid transit systems in the US which do not use third rail covers. The other one I'm aware of, Chicago, doesn't because the design of their third rail shoes - instead of being a paddle-type shoe that extends laterally from the truck shoe beam, Chicago uses sprung pickup shoes that hang vertically from the truck, preventing any obstruction of the third rail from above. So why does Boston not use third rail covers? My guess is a) cost, and b) third rail electrocutions are thankfully extremely rare in Boston.

Same thing with platform screen doors. They are becoming more common especially on new build systems, but they're expensive and difficult to retrofit to existing systems (especially those which are still manually operated), and thankfully the number of incursions of people and things into the pit at stations is rare enough that it isn't seen as a must-do.

Jaymac, interesting tidbit - the segment of the Blue Line which was once streetcar, from Maverick Square to downtown Boston, is the part which now uses third rail. The "new" part from Maverick Square east got catenary because it was thought that third rail icing might be a concern on a line running so close to the ocean, and deicing overhead wire was an easier process. I've also heard that stringing wire on that segment allowed the reuse of some leftover BRB&L catenary towers but I do not know if that is true - there certainly are none still in use today.

These images seem to show that the red line cars in Boston use mechanisms that rely on gravity to hold the pickup to the third rail which look like they might be incompatible with covers.

jwhite07 wrote: ↑Tue Sep 03, 2024 2:20 pm The other one I'm aware of, Chicago, doesn't because the design of their third rail shoes - instead of being a paddle-type shoe that extends laterally from the truck shoe beam, Chicago uses sprung pickup shoes that hang vertically from the truck, preventing any obstruction of the third rail from above. So why does Boston not use third rail covers? My guess is a) cost, and b) third rail electrocutions are thankfully extremely rare in Boston.

Boston equipment once employed 3rd rail apparatus similar to Chicago's. Even after passenger trains were all equipped with more modern shoes, work equipment continued with the old style shoes. To this day, I do not believe the system is void of such equipment.

Also consider the expense of installing such a setup system-wide, which would A.) solve a problem we rarely have and B.) only in certain cases as the covers do not completely prevent contact with the 3rd rail. NYC still experiences such fatalities. The safest form of 3rd rail is probably the under-riding type that Metro-North uses. Next to that, overhead wire is the safest, so long as it remains overhead. 3rd rail never falls from the sky, so it's much easier to be sure you never get near it through no fault of your own.

CRail wrote: ↑Tue Sep 03, 2024 7:48 pm The safest form of 3rd rail is probably the under-riding type that Metro-North uses.

But has its own issues, as with the Valhalla crash.

Yeah, I was about to say the same thing. The under-riding type has caused fatalities.

RandallW, it may be hard to discern from photos, but there is plenty of clearance above the third rail pickup shoes on Boston cars. The shoes are sprung on the inboard or "handle" end to apply a small amount of positive pressure to keep the contact or "paddle" end from bouncing atop the third rail and arcing too much, as well as allowing for some horizontal and vertical movement such as when transitioning from one third rail segment to the next.

CRail, fascinating to think that there might be some work equipment left over that still has the old style shoe type that drops down directly onto the third rail, but the more I think about it the less surprised I am. The T and its predecessors certainly have a long and strong "make do with what ya got" tradition when it comes to work cars.

CRail wrote: ↑Tue Sep 03, 2024 7:48 pm The safest form of 3rd rail is probably the under-riding type that Metro-North uses.

R36 Combine Coach wrote: ↑Wed Sep 04, 2024 12:15 am But has its own issues, as with the Valhalla crash.

Safest form doesn't mean without any danger. I don't see how the Valhalla incident had anything to do with the 3rd rail being over or under-riding. If an identical incident took place somewhere on the LIRR network, I don't see there being a difference in outcome.

I see a difference... top riding third rail doesn't usually sit any higher than a few inches above the regular railhead. That's really not high enough to get caught on equipment or deflected upward. It also has more rigid supports, since gravity works in its favor. The shoes would also be pushing the rail downward.

In the Valhalla incident, the raised rail broke free of the supports which then allowed it to be deflected and possibly lifted upward by the shoe.

Third rail shoes are break away, any downward force on the rail by the shoe is negligible. The rail was deflected upward by the vehicle on the ground, puncturing its fuel tank on it's way to the rail car. A few inches difference isn't going to matter when a vehicle on the ground is pushed down into it. Lastly, over riding third rail is held to its chairs by clips which do little more to hold the rail in place than the weight of the rail itself. The under riding third rail has to be stripped from the tie it's bolted to in order to be lifted.

ANYWAYS... the original point was that under riding was the safest type because it's much more difficult to accidentally make contact with the power source, an isolated incident with an irrelevant primary cause notwithstanding.