Please explain these Green-line signals

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Please explain these Green-line signals

Postby Yellowspoon » Thu Feb 07, 2019 8:27 am

Please explaine these Green Line signals.

Double yellow.
Fifty years ago, I asked an operator what a double-yellow meant. IIRC, they only were at station entrances and it meant that a train was already in the station. The operator was to stop at a double-yellow and then crawl into the station. So far, I've never seen them other than at station entrances. Has anything changed in fifty years?

Yesterday, I made a round-trip from Waban to Longwood. The outbound leg was in car 3900. In addition to the motorman, there was one other MBTA employee (supervisor?) in the car. As we approached Reservoir, outbound, there was a double-yellow just before the switch to Cleveland Circle. The operator came to a stop. Ten (?) seconds later, the operator yelled at the supervisor (sitting in the middle section of the car) that the double-yellow wasn't changing. Pause, pause, pause. Fifteen seconds later, the supervisor(?) tells the operator to proceed. WTF? Was the fact that I was in a type-9 an issue?

What does a red light mean (besides stop)?
On my way inbound to Longwood, I had noticed two MBTA employees standing at the east end of the Newton Center Station. They appeared to be chatting. An hour later, I was westbound. As the train approached Newton Center, there was a red light within sight of the station (and the two MBTA employees). Odd, I thought, I never saw a train in front of us. The car stopped, as expected. Almost immediately, the operator picked up the phone and said something like, "This is car 900 at signel (number) which is red. I will wait one minute before proceeding" and he hung up the phone. One minute later, he crawled into Newton Center station. There was nothing but green signals after Newton Center. What is the speed limit after penetrating a red signal? Were the two idle MBTA employees part of this little scene? (i.e was this a test to see what operators did at red lights?)
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Re: Please explain these Green-line signals

Postby Disney Guy » Thu Feb 07, 2019 10:58 am

Defects could result in what you saw. A red could persist (must have a yellow as the previous signal) if the track circuitry and electronics "thinks" the track ahead is occupied. Looks like the operator did the correct thing, proceed carefully after a minute to see what is going on and perhaps give help at a scene ahead. Double red means stop and stay until directed by a supervisor at the signal or the signal changes to a more favorable indication.

For the double yellow the operator could proceed carefully immediately after stopping as you stated, without saying anything, unless a train order had been issued for that specific location or the operator was specifically directed at that moment to remain stopped.

I would expect that the speed limit would be comparable to street operating circumstances, and/or being able to stop within half the distance that visibility afforded.
Last edited by Disney Guy on Thu Feb 07, 2019 11:32 am, edited 4 times in total.
(To the theater stage manager) Quit twiddling the knob and flickering the lights while the audience is entering and being seated. (To the subway motorman) Quit twiddling the knob and dinging the doors while passengers are getting off and others are waiting to board.
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Re: Please explain these Green-line signals

Postby jwhite07 » Thu Feb 07, 2019 11:00 am

Yellowspoon wrote:Please explaine these Green Line signals.

Double yellow.
Fifty years ago, I asked an operator what a double-yellow meant. IIRC, they only were at station entrances and it meant that a train was already in the station. The operator was to stop at a double-yellow and then crawl into the station. So far, I've never seen them other than at station entrances. Has anything changed in fifty years?


Correct. They require a train to stop, then proceed into the station. That allows trains to "double berth" on platforms.

Yesterday, I made a round-trip from Waban to Longwood. The outbound leg was in car 3900. In addition to the motorman, there was one other MBTA employee (supervisor?) in the car. As we approached Reservoir, outbound, there was a double-yellow just before the switch to Cleveland Circle. The operator came to a stop. Ten (?) seconds later, the operator yelled at the supervisor (sitting in the middle section of the car) that the double-yellow wasn't changing. Pause, pause, pause. Fifteen seconds later, the supervisor(?) tells the operator to proceed. WTF? Was the fact that I was in a type-9 an issue?


Signals are supposed to work the same regardless of car type, so doubt it had anything to do with being on a Type 9.

What does a red light mean (besides stop)?
On my way inbound to Longwood, I had noticed two MBTA employees standing at the east end of the Newton Center Station. They appeared to be chatting. An hour later, I was westbound. As the train approached Newton Center, there was a red light within sight of the station (and the two MBTA employees). Odd, I thought, I never saw a train in front of us. The car stopped, as expected. Almost immediately, the operator picked up the phone and said something like, "This is car 900 at signel (number) which is red. I will wait one minute before proceeding" and he hung up the phone. One minute later, he crawled into Newton Center station. There was nothing but green signals after Newton Center. What is the speed limit after penetrating a red signal? Were the two idle MBTA employees part of this little scene? (i.e was this a test to see what operators did at red lights?)


I have a copy of the Green Line rulebook somewhere in my collection, but I haven't read through it recently. I'm pretty sure that's the procedure, though. If a red signal is encountered, stop and wait, and if after a specified amount of time it hasn't upgraded, call it in, wait one minute more, then proceed at restricted speed prepared to stop short of anything amiss until encountering the next signal.
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Re: Please explain these Green-line signals

Postby Disney Guy » Thu Feb 07, 2019 11:14 am

Approaching Reservoir outbound hopefully the operator eventually got a straight arrow signal indication or in any event read the switch before proceeding over that.
(To the theater stage manager) Quit twiddling the knob and flickering the lights while the audience is entering and being seated. (To the subway motorman) Quit twiddling the knob and dinging the doors while passengers are getting off and others are waiting to board.
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Re: Please explain these Green-line signals

Postby charlesriverbranch » Mon Feb 11, 2019 4:12 pm

Waiting at Eliot for an inbound D-line train the other day, I looked outbound and saw a distant signal flicker from green to yellow and back to green. I saw it do thet last week too; I wonder if there's a dirty relay contact somewhere.
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Re: Please explain these Green-line signals

Postby Disney Guy » Mon Feb 11, 2019 5:18 pm

Could be caused by shorting the rails to each other, perhaps by a prankster using a 5 foot length of wire, or perhaps by a puddle of dirty water on the track (pure water is poor conductor of electricity) simulating occupancy of a block by a train and activating signal circuits, two blocks up ahead.
(To the theater stage manager) Quit twiddling the knob and flickering the lights while the audience is entering and being seated. (To the subway motorman) Quit twiddling the knob and dinging the doors while passengers are getting off and others are waiting to board.
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Re: Please explain these Green-line signals

Postby diburning » Tue Feb 12, 2019 4:32 am

Damp ground plus road salt will do it.
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