Discussion relating to the past and present operations of the NYC Subway, PATH, and Staten Island Railway (SIRT).

Moderator: GirlOnTheTrain

  by Acton Town S5
Hopefully someone will be able to help, I have looked but can not find any mention.
My questions is :

1. Are the tripcock's tested while in service and if so where are these testers located.

2. When a train passes a red signal, is there any sort of indication given to control or somewhere else.

Hopefully I have asked it clear enough if I have not please let me know.


Edit Sorry I should have put New York in case there are other locations.
  by Allan
1) As far as I know the tripcocks are only tested while a car is in the car barn. Testing in service would cause unnecessary delays in service.

2) When a train passes a red signal there is no direct indication given to control. HOWEVER, the stop arm (tripper) will engage with the tripcock and the emergency brakes will immediately activate, stopping the train. The T/O has to contact control via radio to advise them that the train has gone BIE (brakes in emergency). The T/O must then exit the train and go down to the roadbed and check every tripcock on the train (there are 2 on each car) to see that the train did not hit something on the tracks (like garbage or a person). Only after the T/O does this and returns to the cab and reports to control that everything is OK can the train resume. This operation can take at least 15-20 minutes.

When a tripcock engages a stop arm, there is what is called a "strike mark" left on the tripcock. That is, the white paint used on the tripcock will be rubbed off at the point where it contacted the stop arm and is quite noticeable when supervisors check the train.

The situation does not go completely unnoticed. When a train goes by a signal (green, yellow etc), a light goes on for that signal on model boards located in various places along that route (signal towers, line/gap dispatchers offices and in the case of the numbered lines the Rail Control Center) indicating that the signal has gone to red. As a train moves along the route the lights will go on and off as it passes the signals and the signals behind the train go to yellow and then green. A train not moving does get noticed rather quickly. The T/O is then contacted via radio to find out what is going on.

BTW - when a T/O gets on the train at a terminal, it is procedure to visually check the tripcock on the lead car before taking the train into service (I have seen some go down to the roadbed to get a better look). That way they can report any issues (such as strike marks) to the dispatcher so that they won't be blamed for any strike marks that did not occur while the train is under their control.

The above applies to the NYC Subway. PATH is a different situation altogether.
  by Acton Town S5

Thanks for the reply although I am surprised that the tripcocks are tested in the depot and then the trains are allowed to run around without any checks. What I mean is if something happened to the tripcock and the train passed a red signal it might not get tripped. Over here in the UK trains on lines that have tripcocks must be tested at least once every trip and even when there is special working they put in temporary tripcock testers. To give you some idea here are some locations.
District line
Acton Town all platforms
Barons Court westbound
Earls Court all platforms
Upminster Bridge Bridge eastbound/westbound
Upney eastbound

Bakerloo line
Baker Street northbound/southbound
Harrow & Wealdstone southbound
Queens Park northbound

Piccadilly line
Barons Court eastbound
Ruislip westbound
Wood Green eastbound/westbound
See Acton Town

If you check this page you will see a testerhttp://www.districtdave.co.uk/html/signalling.html. Now regarding any indication in the more modern control rooms at Baker Street they get an indication to show that a train has passed a signal at danger they sometimes paint the trainstop arm white although they don't do this very often but after any reported issues the trainstop is checked to see if it has come into contact with anything.
  by Allan
To test them means that the train operator has to go down to the roadbed and manually hit the tripcock with something in order to activate the emergency brakes. That is both time consuming and dangerous and generally unnecessary as tripcock failure on NYC Subway cars is very, very rare.

If for some reason the tripcock was not functioning properly then the air brake system on the train would not charge up fully on the train when the train operator sets the controls up. A train braking system has to charge fully to 110 lbs psi before the train operator gets "indication" (doors are closed and locked and brakes fully charged) at which point the brakes will release and the train can move. If it charges to anything less than that then the train will not move (the brakes will not release) and the train will not take on motive power. On the newer cars model R142 and up, everything is monitored by an onboard computer so if anything is amiss it will show on the train operators screen and depending on what the problem is the train can't be moved unless it is resolved.

Certain issues can be by-passed (special by-pass button) but in most cases when the by-pass is used the train will not be in passenger service and will be moved to the train yard for servicing.

BTW - the all the stop arms are painted yellow on the top/contact point so they can easily be seen (indoors and outdoors). The tripcocks are painted white.
Last edited by GirlOnTheTrain on Fri Sep 23, 2016 10:45 am, edited 1 time in total. Reason: There is no need to quote the post immediately preceding this one.
  by Acton Town S5
Tripcock failures over here in the UK is rare but any testing is done by staff in the depots/sidings, drivers normally only check if something is suspected. The trouble over here is that when there is a signal failure most trains would have marks on the tripcock arm as well as the trainstop so unless there has been a serious incident it is normally hard to prove who was the one responsible. All the modern stock have black boxes so that everything was recorded and available for download if there were any incidents. In the link I put was the actual tester where the tripcock arm went through and pressed the lightly greased ramp down before the train went through a light would be switched on by the train via a track circuit, if the light went out all in order but if not then the driver would be aware and then make checks. Sometimes when trains went through the tested too fat the train would get tripped but as long as the light went out it could stay in service.
  by Allan
This shows that different systems have different methods/rules of train servicing and controls.

The MTA does have some staff to do some "in route" testing/servicing but that is only when a train breaks down while in service (these people are call "Road Car Inspectors"). Any routine testing is done in the Train Yard/Car Barn when a train is being repaired or otherwise serviced.

If there is a signal circuit problem on the NYC Subway, all affected signals immediately go to red and the stop arm goes up (and all the lights on the model boards light up). I have been on a train where this has happened a few times (over many years). The lead car went by the signal (which was green at the time) but we got tripped by the tripcock on one of the cars behind. The last time I remember it was close to 1 hour before they got the signals in working order (and I got to work late). Thankfully it doesn't happen that often.
  by Acton Town S5
That does indeed show how two systems with similarities can be very different. Over here in the UK the trains are checked before going into service the driver role has changed over the years on the older stock before going One Person Operation they were given 15 mins preparation time and at one time this included 4 walks of the train, although this did not include the tripcock. On the older stock it was not unknown for a tripcock to become defective in service and this was normally after passing a location with a tester, what would happen is a test would be completed successfully but during that test the tripcock was either moved slightly or a small piece was broken off and when the next test was done the train would fail to put out the light and not get tripped. Sometimes the train would put out the light but get tripped normally the driver was going to fast. On the newer trains this has not happened as much, but trains still get checked each trip.
Last edited by GirlOnTheTrain on Fri Sep 23, 2016 10:44 am, edited 1 time in total. Reason: There is no need to quote the post immediately preceding this one.
  by GirlOnTheTrain
Ok, aside from the initial few posts...this is going around in circles and has very little relevance to the MTA anymore.

If anyone has anything to contribute, they can message me.