Red lights on the Green Line

Discussion relating to commuter rail, light rail, and subway operations of the MBTA.

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Re: Red lights on the Green Line

Postby bostontrainguy » Sun Jan 05, 2014 9:42 am

Personally I feel the safest situation for the Greenline is all trains moving at about the same speed separated by proper block signals. These "safety stop" signals are not really doing anything to improve safety. In fact yesterday was a great example of how they could cause problems. The track between Boylston and Arlington westbound was extremely slippery for some reason. Drivers had to deal with slippery rail and then a train STOPPED ahead on the curve and slope. The potential for collision was very high. Yesterday could have presented a strong case against these things.
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Re: Red lights on the Green Line

Postby Disney Guy » Sun Jan 05, 2014 10:14 pm

Trip cocks would not work in the Green Line Central Subway without extensive reconfiguration of blocks. Should a trip cock perform its function, there might not be enough distance between the red signal just overrun and the rear of the train up ahead to come to a stop without a collision anyway.
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Re: Red lights on the Green Line

Postby diburning » Sun Jan 05, 2014 10:42 pm

Right, because if the train, for example a 3 or 4 car train, straddles more than one block, a trip cock can cause delays because it would probably trip the last car.

As it is right now, even with two car trains, the signal drops to red after about half of the first car passes the signal. If they added timers, it might slow things down. Right now, the signals along with line-of-sight operations seems to work. Why fix it?
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Re: Red lights on the Green Line

Postby TrainManTy » Sun Jan 05, 2014 11:15 pm

Gerry6309 wrote:Remember in 1897, the tunnel was populated by 25' wooden closed cars and 9 bench opens!!!, running very close to each other and depending on hand brakes to stop. There were no signals. Accidents were unheard of.


CRail wrote:Top speeds were also a bit lower, and I would suspect that acceleration was as well.


Also of note is that the lighter wooden cars could likely stop faster than today's heavy equipment. I don't imagine it's as extreme as heavy rail equipment (which are governed by FRA crashworthiness standards and are much, much heavier than wooden coaches of old) but it's another thing to keep in mind.
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Re: Red lights on the Green Line

Postby Gerry6309 » Mon Jan 06, 2014 11:12 am

Cosmo wrote:
Gerry6309 wrote:Remember in 1897, the tunnel was populated by 25' wooden closed cars and 9 bench opens!!!, running very close to each other and depending on hand brakes to stop. There were no signals. Accidents were unheard of.

"Unheard of" or just not heard about?


The Elevated won so many safety medals that the award was retired! The shelf life of an innattentive motorman was very short. Think about those open cars running in the subways. The opportunity for disaster was immense, yet their were very few events. The fact is that crews and riders were more careful back then.

Another point: The Elevated designed its cars for a top speed of 25 MPH. Type 7 and 8 cars can do fifty - and they do - even in the subway! A Type 5 was good for 25 - downhill, with a fail wind! (Except for the "high speed" cars which weren't allowed in the subway. Neither were the Type 4s with Field Shunts which had some bad wrecks on the street. The PCCs were the first fast cars in the subway, And thats when the accidents started.
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Re: Red lights on the Green Line

Postby CRail » Mon Jan 06, 2014 11:42 am

diburning wrote:Right, because if the train, for example a 3 or 4 car train, straddles more than one block, a trip cock can cause delays because it would probably trip the last car.

As it is right now, even with two car trains, the signal drops to red after about half of the first car passes the signal. If they added timers, it might slow things down. Right now, the signals along with line-of-sight operations seems to work. Why fix it?

Trip arms don't rise until the block has been cleared, during which time the previous signal remains red (and arm up), which is currently the case anyway (minus the trip). The blue line has blocks far shorter than the length of a train, and this isn't a problem for them*. Disney's point is that there is potential for a tripped train to rear end its leader despite the fact that it had been tripped. While that is a possibility, all of the serious crashes causing the call for an upgrade would have been prevented if trips were in place. Regarding the most recent Boylston accident; Even if the offending train were still allowed to make contact with the train berthed in the station, the speed at impact would have been greatly reduced and therefor the amount of damage and number of injuries would be as well. Plus, the stopping force caused by the stationary car would have combined with that of the already applied breaks of the moving train, additionally minimizing damage by reducing the amount of energy absorbed by the stopped car.

No one has said anything about timers. Timers are for speed control, not positive stop (and, for the record, their whole point is to slow things down). The time it takes for a signal to physically change has nothing to do with anything. "Signals along with line-of-sight" doesn't seem to work because we're having this conversation. Because of what has happened in spite of the signal system, the T forces trains to stop at various locations regardless of whether or not the conditions require it. My stance has been that, in lieu of something better, this is the correct procedure to ensure an accident doesn't happen. It's also been that the "something better" is not an automated system, but something much simpler like trips.

*See Bowdoin Station eastbound, or just about any subway station of the NYCTA, where trip arm equipped block signals are positioned half way down platforms. In the cases of NYC, there are sometimes multiple signals within the length of a platform.
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Re: Red lights on the Green Line

Postby Gerry6309 » Mon Jan 06, 2014 12:05 pm

CRail wrote:*See Bowdoin Station eastbound, or just about any subway station of the NYCTA, where trip arm equipped block signals are positioned half way down platforms. In the cases of NYC, there are sometimes multiple signals within the length of a platform.

And even with all the trips NYCTA has added immense numbers of timers to its runs between stations, especially on express tracks. Also in NY you can "key by" without leaving the cab, in Boston you can't.
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Re: Red lights on the Green Line

Postby bostontrainguy » Mon Jan 06, 2014 1:00 pm

Gerry6309 wrote: Another point: The Elevated designed its cars for a top speed of 25 MPH. Type 7 and 8 cars can do fifty - and they do - even in the subway!


Both Type 7s and 8s can now only reach 40 mph even on the Riverside line which was run at 50 mph many years ago. If they get up to 40 mph in the subway, it's for a very short stretch between Hynes and Copley or Copley and Arlington. It's pretty hard to get up there anyplace else in the subway.
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Re: Red lights on the Green Line

Postby bostontrainguy » Mon Jan 06, 2014 1:45 pm

CRail wrote: the T forces trains to stop at various locations regardless of whether or not the conditions require it. My stance has been that, in lieu of something better, this is the correct procedure to ensure an accident doesn't happen.


Let's look at this thing logically. There was a collision on your subway system at a spot that has a blind curve and a downgrade. Maybe it was driver inattention, maybe it was brake failure, maybe it was a faulty signal, maybe it was slippery rail. Whatever the case, a train-on-train accident occurred and you have to do something.

So you decide to make it mandatory for EVERY train to STOP at this location in the future. Now realistically, do you think you have DECREASED the possibility of a collision at that spot or INCREASED it? I firmly believe that the more times you stop the trains in the subway, the more you increase collision potential. If there isn't a stopped train ahead to run into, there is no collision.

In addition you need to consider the real problem of elderly and disabled passengers, uninitiated tourists and inebriated or inattentive passengers especially standing in Type 8s with stairs. Passengers are already subjected to the unexpected and often violent Greenline justling and jerking. Adding artificial stops and starts again increases the potential of accidents, and the T considers it an "accident" if someone simply falls and injures themselves on a train.

The constant starting and stopping on the Greenline increases the potential for all types of "accidents" and creates the impression that it is a ride on the Toonerville Trolley and not a modern efficient transit system. It's time for the T to take a real long hard look at the Greenline and see what can be done to make it a better passenger experience,
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Re: Red lights on the Green Line

Postby MBTA1016 » Mon Jan 06, 2014 3:42 pm

bostontrainguy wrote:
CRail wrote: the T forces trains to stop at various locations regardless of whether or not the conditions require it. My stance has been that, in lieu of something better, this is the correct procedure to ensure an accident doesn't happen.


Let's look at this thing logically. There was a collision on your subway system at a spot that has a blind curve and a downgrade. Maybe it was driver inattention, maybe it was brake failure, maybe it was a faulty signal, maybe it was slippery rail. Whatever the case, a train-on-train accident occurred and you have to do something.

So you decide to make it mandatory for EVERY train to STOP at this location in the future. Now realistically, do you think you have DECREASED the possibility of a collision at that spot or INCREASED it? I firmly believe that the more times you stop the trains in the subway, the more you increase collision potential. If there isn't a stopped train ahead to run into, there is no collision.

In addition you need to consider the real problem of elderly and disabled passengers, uninitiated tourists and inebriated or inattentive passengers especially standing in Type 8s with stairs. Passengers are already subjected to the unexpected and often violent Greenline justling and jerking. Adding artificial stops and starts again increases the potential of accidents, and the T considers it an "accident" if someone simply falls and injures themselves on a train.

The constant starting and stopping on the Greenline increases the potential for all types of "accidents" and creates the impression that it is a ride on the Toonerville Trolley and not a modern efficient transit system. It's time for the T to take a real long hard look at the Greenline and see what can be done to make it a better passenger experience,


Here's a bright idea call a cab there's hundreds of them in the city. The signals are for safety not to keep ur sorry butt happy.
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Re: Red lights on the Green Line

Postby deathtopumpkins » Mon Jan 06, 2014 6:17 pm

Mbta fan wrote:Here's a bright idea call a cab there's hundreds of them in the city. The signals are for safety not to keep ur sorry butt happy.


Telling someone unhappy with the quality of T service to "take a cab" is not an acceptable solution. A cab ride across the city would cost you $20 at a bare minimum. That's 10 times as much as a T ride. And many of these passengers bostontrainguy was complaining about having issues (elderly, disabled, etc.) can't afford to depend on cab rides for basic transportation. I don't think 95% of the people who ride the T could simply always take a cab instead. I know you're young and have probably never paid for a cab ride before, but they are expensive.

And for the record I agree with him completely. Multiple times I've seen an elderly or disabled passenger fall due to a sudden start or stop on the Green Line. In fact, a handful of those incidents have been serious enough to alert the driver. To be fair to the T though, if drivers actually accelerated and braked gently rather than flooring it up to 45 mph and then immediately slamming on the brakes this wouldn't be nearly as much of a problem.
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Re: Red lights on the Green Line

Postby MBTA1016 » Mon Jan 06, 2014 6:53 pm

deathtopumpkins wrote:
Mbta fan wrote:Here's a bright idea call a cab there's hundreds of them in the city. The signals are for safety not to keep ur sorry butt happy.


Telling someone unhappy with the quality of T service to "take a cab" is not an acceptable solution. A cab ride across the city would cost you $20 at a bare minimum. That's 10 times as much as a T ride. And many of these passengers bostontrainguy was complaining about having issues (elderly, disabled, etc.) can't afford to depend on cab rides for basic transportation. I don't think 95% of the people who ride the T could simply always take a cab instead. I know you're young and have probably never paid for a cab ride before, but they are expensive.

And for the record I agree with him completely. Multiple times I've seen an elderly or disabled passenger fall due to a sudden start or stop on the Green Line. In fact, a handful of those incidents have been serious enough to alert the driver. To be fair to the T though, if drivers actually accelerated and braked gently rather than flooring it up to 45 mph and then immediately slamming on the brakes this wouldn't be nearly as much of a problem.


Agreed, but it's better then everyone on here explaining over and over again to him why they are needed. The signals are for safety and if he doesn't like it then tough luck, they are there for a reason and the T isn't going to get rid of them anytime soon.
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Re: Red lights on the Green Line

Postby deathtopumpkins » Mon Jan 06, 2014 7:17 pm

Mbta fan wrote:Agreed, but it's better then everyone on here explaining over and over again to him why they are needed. The signals are for safety and if he doesn't like it then tough luck, they are there for a reason and the T isn't going to get rid of them anytime soon.


Can you please tell me then why he isn't allowed to question why they are needed "for safety"? We all know that's the argument for why they're there. But that doesn't mean they're always going to be there, and it doesn't mean it wouldn't make sense to get rid of them.
If the T is ever going to throw off the negative public image it has created over the past decades, then progress needs to be key. They need to stop saying things like "but this is how we've always done it". I think insisting on things like these signals is significantly holding the T back.
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Re: Red lights on the Green Line

Postby MBTA1016 » Mon Jan 06, 2014 9:48 pm

It's even explained by knowledgable people over and over. Read the previous pages. There's blind corners and stuff inside the tunnels. Read the thread and you'll see that.

The thing holding the T back is the deficit they are always in but that's for a seperate disscussion. Removing these signals is at the bottom of the priority list if its even on it. U ever see how jammed the green line gets on rolling rally days. They do what they can with what they got and its been working for the last 100yrs. Sorry if I don't agree with you but we are beating a dead horse here. Safety is priority, one persons commute out of thousands and thousands daily isn't a major concern to the T. He's getting where he wants to be. The T accomplishes that in a manner they deem is safe for everyone involved.
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Re: Red lights on the Green Line

Postby MBTA1016 » Mon Jan 06, 2014 10:05 pm

Gerry6309 wrote:Most of these safety stops deal with obstructed views. The two at Muddy River where every train stops but nobody ever boards, are due to the curves entering Hynes and Kenmore Interlocking respectively. Both of these locations are just around the curve and often have occupied blocks. Stopping insures these curves are entered at safe speeds. They are a pain but are there for YOUR safety. The same got for Charles Crossover westbound and Kenmore Eastbound from Beacon. Others are because of steep grades or interlocking approaches or both. Take them out and an accident WILL happen.


Here Connor that's why they are needed. I'm not arguing with u anymore about this since we are obviously butting heads(don't want to make this whole thread an argument between me and you).
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