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 CRail » Tue Jun 25, 2013 9:30 pm

Traveling at a slow speed does not prove that you have the ability to stop. This is protection against possible faulty equipment more than operator error, but it reduces the likelihood and/or severity of both.

Green line dispatchers are blind to signal indications and switch positions, except for what may be in a camera's view.
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Re: Red lights on the Green Line

Postby MBTA1016 » Tue Jun 25, 2013 9:42 pm

I don't want to take over the moderators job here, suggesting this thread be closed on account of people not understanding why these signals are needed and will need it explained over and over.

Safety is a priority of all tranist systems, what one person thinks means nothing to them. Here's a favorite quote of mine
"Opinions are like mouths, everyone has one".
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Re: Red lights on the Green Line

Postby Yellowspoon » Wed Jun 26, 2013 6:56 am

sery2831 wrote:As I explained the stop is necessary to make the operator aware on how the train will brake/stop. Every train stops differently, between equipment and passenger load. This is the safest way to make this happen!
You haven't explained anything. You've just repeated your unsubstantiated declaration a second time. Please support that statement. Why is the green line different? They don't have test stops on the E trains inbound nor on the red/blue/orange/PATH/TGV/IRT/BMT/BART/CTA lines. Also, by the time a green line train gets to a portal, the driver has already stopped the car at least a dozen times. They are well aware how the train will brake/stop by that point. In addition, the C/D trains must stop just before Beacon Junction. The trains weight/mass is exactly the same when it arrives at the red signal half way to Kenmore. I don't see how your theory could possibly be true.

As for varying loads, I don't think that makes a difference. PATH trains have sensors that detect the passenger weight of each car so the the accelerator/brakes act uniformly regardless of passenger load. I assume the 7s/8s are so equipped.

And still, no one has explained the purpose of the 6-8 second dwell at a complete stop.
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Re: Red lights on the Green Line

Postby BandM4266 » Wed Jun 26, 2013 7:56 am

Yellowspoon wrote:
sery2831 wrote:As I explained the stop is necessary to make the operator aware on how the train will brake/stop. Every train stops differently, between equipment and passenger load. This is the safest way to make this happen!
You haven't explained anything. You've just repeated your unsubstantiated declaration a second time. Please support that statement. Why is the green line different? They don't have test stops on the E trains inbound nor on the red/blue/orange/PATH/TGV/IRT/BMT/BART/CTA lines. Also, by the time a green line train gets to a portal, the driver has already stopped the car at least a dozen times. They are well aware how the train will brake/stop by that point. In addition, the C/D trains must stop just before Beacon Junction. The trains weight/mass is exactly the same when it arrives at the red signal half way to Kenmore. I don't see how your theory could possibly be true.

As for varying loads, I don't think that makes a difference. PATH trains have sensors that detect the passenger weight of each car so the the accelerator/brakes act uniformly regardless of passenger load. I assume the 7s/8s are so equipped.

And still, no one has explained the purpose of the 6-8 second dwell at a complete stop.


They most certainly have a test stop on the E line, if they are express past northeastern then they must stop before going into portal, as a safety stop.

The cars all act differently in different conditions. Your theory of the operator has stopped the car at least a dozen times doesn't work either , most stops are on level rail again I said most!! They haven't stopped on an incline a dozen times with that car, if the rails are wet from drizzle ( I have been told that drizzle is worse then poring rain as its enough to bring out the oils and make it slippery), if there is ice on the rail. How will the train handle?
If the car has a heavy load or light most certainly affects its operation! If it didn't make a difference then those sensors that you claim PATH trains have would be pointless!

Again what does 6-8 seconds add to your day? I would assume that the dwell is more of the time that it takes for the operator to go from brake to accelerator and for the car to respond to this demand. If you don't like the 6-8 second delay take the bus and see how much time it will take vs taking the greenline!

I think I have wasted enough of my time on this as I was typing up this I realized that there is no real way to answer stupid junk without making oneself DUMB in order to make a clear enough point! If you didn't understand it from me, the moderator or GP40MC 1116 then you won't get it the next few times! I am not paying any more attention to this stupidity on this thread
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Re: Red lights on the Green Line

Postby Yellowspoon » Wed Jun 26, 2013 8:49 am

GP40MC 1116 wrote:It's been explained here more than once why the T has stop signals in strategic locations for safety related reasons. Therefore those signals are not "pointless". ...
Don't you think I know that? Please exlpain what the safety issues are and why they can not be handled some other way. Amtrak trains (and TGV trains) don't have red lights to solve safety problems, they fix the problems so that the trains continue to run quickly. And while your at it, please tell me what possible safety issue requires a train to dwell at a complete standstill?

BandM4266 wrote:Sounds to me like this person needs to get a life! 6-8 seconds for a stop and proceed adds no time at all to a commute, the writer wasted more time writing up this article, presumably on company time then it took for the train to stop and move on!
It's a bit presumptious for you to impose YOUR standards on 48,000 green line passengers as well as myself. It's not 6-8 seconds just once for me. It's 6-8 seconds four times a day, five times a week, 52 weeks per year, for 48,000 B/C/D passengers. 97,000 man-hours per year down the toilet. Is that "no time at all"? You want me to get a life? Here it is: 97,000 hours. If you still think 6-8 seconds is trivial, stop your car on Storrow Drive every day for 8 seconds during rush hour. If arrested for obstructing traffic, tell the judge to get a life, because you only obstructed it for 8 seconds.

Six seconds here and eight seconds there, and pretty soon, you're talking real time. When Riverside opened in 1959, the MTA claimed a running time of 35 minutes to Park Street. I timed three recent trips at 41, 43, and 51 minutes. Even if we throw out the 51 minute observation as an exception, the other two average 20% longer than 1959. According to the first paragraph of http://en.wikipedia.org/wiki/Riverside_%28MBTA_station%29 the scheduled time is now 46 minutes, 31% slower than 1959. 55 years ago, the Old Colony Line went from South Station to Buzzards Bay in 75 minutes. The Cape Flyer needs 98 minutes, 31% slower than the Old Colony counterpart. And the rocket ride from Buzzards Bay to Hyannis averages 24 miles per hour even though there are no stops. And here's a sign you'll never see again: http://2.bp.blogspot.com/-RgNxpsmGr58/T1Js0WREggI/AAAAAAAAAX4/-60U396LJW4/s1600/8min.JPG (Unless they move it to Kendall)

Again, I am not saying to simply eliminate the red lights, I'm saying that the MBTA should correct the underlying problems that require the red lights in the first place. Then again, the MBTA takes its cue from Ernestine (a.k.a. Lily Tomlin), "We don't care. We don't have to"

Notes: The figure of 48,000 was derived from page 26 of http://www.mbta.com/uploadedfiles/documents/Bluebook%202010.pdf. I assumed that 75% of those B/C/D paying passengers entered the subway. The 97,000 man-hours is based solely on the 7 second dwell at a complete stop. If I use the total 18-seconds delay cause by each of four red lights, that works out to a total of 249,000 man hours wasted each year because the T is unwilling to solve the safety issue some other way. If we capitalize 249,000 man hours at $8.00 per hour (minimum wage) and use a capitalization rate of 5%, that comes to $39 million dollars. That doesn't include wasted electricity nor equipment wear. Surely, the safety issues at five red lights could be resolved for a lot less than $39 million dollars.
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Re: Red lights on the Green Line

Postby Yellowspoon » Wed Jun 26, 2013 9:30 am

BandM4266 wrote: ... Your theory of the operator has stopped the car at least a dozen times doesn't work either , most stops are on level rail again I said most!! They haven't stopped on an incline a dozen times with that car, if the rails are wet from drizzle ( I have been told that drizzle is worse then poring rain as its enough to bring out the oils and make it slippery), if there is ice on the rail. How will the train handle? ...
B trains have an incline at St. Paul Street, Warren Street, and Washington Street. C trains have an incline Washington Square and St. Paul's street. The stop-and-take-a-break red light 400m after Beacon Junction is not on an incline, so what's the issue here? If the rails are wet, that's what the electromagnetic track brakes are for, not only on the green line but on just about all subway cars. As for ice, I have yet to see any on the rails in the subway, so why did you bring it up.

What's different? What non-repairable safety issues do green line trains have that orange/blue/red don't have?
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Re: Red lights on the Green Line

Postby boblothrope » Wed Jun 26, 2013 11:37 am

CRail wrote:The theory is if your brakes have failed, you have more time to figure out what to do than if you realize your brakes failed 50 feet away from the car ahead of you, or even closer to a sharp curve. It's not for speed control, it's to ensure the operator still has control.


Care to provide a cite that the stop signals are there to handle brake failures, and not just to prevent operator error? I've never heard of *any* rail system that requires multiple full-stop running brake tests out on the road during every revenue run.

And what exactly would an operator do if the brakes failed at an all-stop signal? Get on the radio and yell, "Out of the way!"? And how would that help for a speed restriction at a curve?
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Re: Red lights on the Green Line

Postby boblothrope » Wed Jun 26, 2013 11:50 am

sery2831 wrote:More and more stop signals have been installed? What are the recent additions? I am not aware of these.


There are several on the new tracks between North Station and Science Park.

boblothrope wrote:If the safe speed for a stretch of track is 10 mph, make sure the drivers go 10. Not 0 and then 10.


sery2831 wrote:As I explained the stop is necessary to make the operator aware on how the train will brake/stop. Every train stops differently, between equipment and passenger load. This is the safest way to make this happen!


How often do trains skid through the all-stop signal because the operator wasn't aware how the train would handle? If it never happens, then there's no need for a redundant safety stop before the stop signal that really matters.
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Re: Red lights on the Green Line

Postby sery2831 » Wed Jun 26, 2013 12:59 pm

boblothrope wrote:
sery2831 wrote:More and more stop signals have been installed? What are the recent additions? I am not aware of these.


There are several on the new tracks between North Station and Science Park.


Not ADDED, that is new track, and the design requires those safety stops before entering yard trackage.

boblothrope wrote:If the safe speed for a stretch of track is 10 mph, make sure the drivers go 10. Not 0 and then 10.


sery2831 wrote:As I explained the stop is necessary to make the operator aware on how the train will brake/stop. Every train stops differently, between equipment and passenger load. This is the safest way to make this happen!


boblothrope wrote:How often do trains skid through the all-stop signal because the operator wasn't aware how the train would handle? If it never happens, then there's no need for a redundant safety stop before the stop signal that really matters.


Happens all the time. I do not ride the Green Line often and many times the operator passes it by a few feet. They come to a complete stop and proceed. So I suppose that ends this discussion.

Also trying to bring in Rapid Transit to this discussion is not logical because if those pass a stop signal they have a safety system to stop the train.
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Re: Red lights on the Green Line

Postby sery2831 » Wed Jun 26, 2013 1:08 pm

Yellowspoon wrote:
sery2831 wrote:As I explained the stop is necessary to make the operator aware on how the train will brake/stop. Every train stops differently, between equipment and passenger load. This is the safest way to make this happen!
You haven't explained anything. You've just repeated your unsubstantiated declaration a second time. Please support that statement. Why is the green line different? They don't have test stops on the E trains inbound nor on the red/blue/orange/PATH/TGV/IRT/BMT/BART/CTA lines. Also, by the time a green line train gets to a portal, the driver has already stopped the car at least a dozen times. They are well aware how the train will brake/stop by that point. In addition, the C/D trains must stop just before Beacon Junction. The trains weight/mass is exactly the same when it arrives at the red signal half way to Kenmore. I don't see how your theory could possibly be true.


Braking changes constantly on rail vehicles. On rapid transit, trains are spaced and if a train violates a signal the train is stopped. And by design the spacing allows for that stop past the signal. On the Commuter Rail(railroad equipment) every train brakes differently, EVEN if it's made up by the same cars. And a running test is required for those trains, something not possible on a light rail car. On the Green Line there is NO spacing what so ever. In order for this, the operator needs to demonstrate over and over he or she can safely stop the train. We can get rid of the safety stops, and allow one train in every other block. That would space out the trains and allow them to purely operate on signal and never have to come close to each other. That would be interesting in Park St for sure!
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Re: Red lights on the Green Line

Postby CRail » Thu Jul 04, 2013 2:44 pm

Talk about a traffic jam!
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Re: Red lights on the Green Line

Postby Gerry6309 » Fri Jul 05, 2013 7:45 pm

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.
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Re: Red lights on the Green Line

Postby CRail » Mon Jul 08, 2013 10:10 am

...unless they're replaced by a more effective positive stop system (blue line, NYC, etc) which would be feasible and as I explained before, wouldn't destroy the line the way ATO has wrecked the Red and Orange lines, and the central subways of Philadelphia's and San Fransisco's light rail systems. THAT is the way to go in my opinion. Until then, however, what we have is the next best thing.
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Re: Red lights on the Green Line

Postby bostontrainguy » Tue Dec 10, 2013 1:27 pm

The Greenline is frustratingly slow to begin with. These "safety" signals do nothing but slow down service even more and create the real possibility that elderly passengers or inebriated passengers could actually get injured due to an increase of unnecessary stops and starts in addition to the constant jerking about that they are already subjected to.

Sure safety is important, but the T always over reacts. They just turned the signal westbound before Boylston into a red vs. a double-yellow due to the recent collision there. This again has slowed service down and in reality would a "dozing" driver had stopped either way?

These signals may stop service for only a few seconds here and there, but they do add to the overall travel times and lead to a greater perception that the Greenline is pathetically slow and outdated. Plus the constant stop and starts make the ride even more unpleasant.

These signals are not for "brake testing" as mentioned by others. They are intended to slow service down . . . period. Since you are talking about a system with 3 mph, 6 mph, 10 mph speed limits and a 25 mph maximum subway speed, do you really think they make things any safer?

The T should be looking for ways to make the Greenline faster, not slower.
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Re: Red lights on the Green Line

Postby ryanov » Sat Dec 14, 2013 11:47 am

I am really unimpressed with some of the answers the original poster is getting to a perfectly legitimate question. "What are these for and isn't there a less onerous way of doing this?" and talking about the energy waste and obvious congestion problems it may cause is totally reasonable. And if folks can't do the math that 6-8 seconds per train per stop times the number of people is a LOT of time, that is not his problem either. Instead he gets a bunch of answers like "OMG, do you want cars crashing into each other?!!?!?!one!!!" Grow up. It may be a necessary evil, it may be an unnecessary evil. There are reasons that they are there, and they may or may not be historical at this point (eg. better technology exists). But I can tell from the tone of the people answering that they don't have insider knowledge, so what is with the attitude?
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