PATH signal system/tunnels

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

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train2
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PATH signal system/tunnels

Post by train2 »

Took my first ride on PATH yesterday. I rode the entire system and had the front window for all the legs.

What is the deal with PATH's signal system? A great number of signals, more than 50-60 percent, would be one more restrictive indication and clear just as we neared them. In one situation several reds were passed a some speed when they would clear at the absolute last second. One signal never cleared in my field of view but we did not stop so it must have come up with a single second to spare.

What struck me was motorman was not approaching preparing to stop but running as if he knew this was going to happen. Are these a type of timing or speed reducing signal? What happens if a train gets by one of these while still red? I assume we would have stopped since there were trips on the track. Are passing transit signals as serious as passing a red on a big railroad? I also could not tell much of difference between interlocking signals from regular lineside signals. Is there anyway to tell?

I saw the Interlocking board at Hoboken. Where else does PATH have a dispatcher or towers?

I don't spend a lot of time on transit systems, but the PATH tunnels struck me as the most cramped/restrictive I have ever been in. Would you agree. Anyone know the dimensions?

T2

Terry Kennedy
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Re: PATH signal system/tunnels

Post by Terry Kennedy »

train2 wrote:What is the deal with PATH's signal system? A great number of signals, more than 50-60 percent, would be one more restrictive indication and clear just as we neared them. In one situation several reds were passed a some speed when they would clear at the absolute last second. One signal never cleared in my field of view but we did not stop so it must have come up with a single second to spare.

What struck me was motorman was not approaching preparing to stop but running as if he knew this was going to happen. Are these a type of timing or speed reducing signal? What happens if a train gets by one of these while still red? I assume we would have stopped since there were trips on the track. Are passing transit signals as serious as passing a red on a big railroad? I also could not tell much of difference between interlocking signals from regular lineside signals. Is there anyway to tell?
First, don't say "motorman". The title is "Engineer"

Yes, there are people in the system who have many years of experience and can tell to a fraction of a second when a signal will clear. At least until someone changes the signal timing, which has been known to happen. Even so, sometimes someone will charge the signal a bit too aggressively and either do some last-minute braking or get tripped. (Yes, there are trip arms).

New engineers (at least in my experience) get trained by the old-timers who pass along their secrets (for example, when running in the reverse direction in Tunnel B, some of the signals don't have trip arms, so you can run them).

The occasional (minor) indescretion seems to get a pass. In the PATH system, lineups are set by the towers, not by the engineers (there are no "punch boxes" like on NYC Transit). For example, two trains I've been on: First, around the time that service changes to late-night, got a wrong lineup toward HOB (this was the last direct JSQ train). The engineer radioed the dispatcher, who said "How far into it did you get?" and the engineer replied "About 3 feet". Dispatch said "Well, back it up and try again". We backed up, they reset the interlocking, and away we went. Second case - engineer didn't notice their 33Rd train took the wrong lineup and got most of the way to Exchange Place before they noticed. That was a career-ending move.

The signal format is a bit different from NYC Transit and people used to that system often get confused. Just because there's a red aspect on the signal doesn't necessarily mean it is for your train - interlocking is "bottom left, top right" and the path (no pun intended) you're not taking will be red. Also, unlike NYCT chaining (signal numbers are distances in feet / 100), PATH signals are consecutive numbers (with A, B, etc.) added if new signals are added between existing ones.
I saw the Interlocking board at Hoboken. Where else does PATH have a dispatcher or towers?
Journal Square (west enf of Tracks 1 & 2), World Trade Center (north end of Tracks 2 & 3). A bunch out west past JSQ.
I don't spend a lot of time on transit systems, but the PATH tunnels struck me as the most cramped/restrictive I have ever been in. Would you agree. Anyone know the dimensions?
Approximately the same as the original IRT (4/5/6 below Times Square, 1/2/3 north). The original design was for full-size freight with steam power (they started in 1874, though a lawsuit kept it from being more than a pit at 15th Street until 1879). Companies repeatedly went bankrupt trying to continue the work, reducing the tunnel diameter each time. Parts of Tunnel A (heading to NJ from 33rd) are the original large diameter and you can see the original brickwork from the 1879-1882 work - the iron rings in the "newer" tunnels didn't get used until the turn of the century. What makes it seem more cramped is the visible rings. The original IRT was mostly cut-and-cover, so it appears larger, being a square box instead of a circle.

If you want exact dimensions for the various tunnel types, let me know and I'll dig 'em out and post.

train2
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Re: PATH signal system/tunnels

Post by train2 »

Good explanation so far. Can you elaborate as to why so many signals change like they do? Is it to control speed, space out trains? I have not viewed a signal system work this way before.

I did notice the conductor of the Path train had Conductor on her shirt. None of the engineers had any markings on them so I will note the name change from "motor dude" to engineer.

T2
Last edited by train2 on Mon Apr 26, 2010 10:36 am, edited 2 times in total.

Terry Kennedy
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Re: PATH signal system/tunnels

Post by Terry Kennedy »

train2 wrote:Good explanation so far. Can you elaborate as to why so many signals change like they do? Is it to control speed, space out trains? I have not viewed a signal system work this way before.
If the previous signal was a double-yellow, it was almost definitely a timer and the following red will change if you come up on it at the proper speed or slower.

I should mention that there is at least one exception to the "bottom left / top right" interlocking signal rule. The one that governs whether you go to HOB or Pavonia/Newport when you get to the NJ end of Tunnel A is an oddball for some reason. It has a [L][R] lightbox next to it to explain what it is trying to say. :-)
I did notice the conductor of the Path train had Conductor on her shirt. None of the engineers had any markings on them so I will note the name change from motor due to engineer.
No problem - I just figured I'd spare you the lecture if you ever talk to one and address them improperly.

Traditionally, there wasn't a dress code as it wasn't a customer service position. Since 9/11, most have changed to wearing black slacks and a burgundy or gray polo shirt with "[PATH Logo] Transportation Division" embroidered on the front.

train2
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Re: PATH signal system/tunnels

Post by train2 »

I saw some of the new cars that had 3 doors along the side. From the outside looking in, do those cars have much seating?--it looked like the car was mostly doors.

Terry Kennedy
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Re: PATH signal system/tunnels

Post by Terry Kennedy »

train2 wrote:I saw some of the new cars that had 3 doors along the side. From the outside looking in, do those cars have much seating?--it looked like the car was mostly doors.
The PA-4's (the previous series, from the mid-80's) also had 3 sets of doors. [And poorer planning - wheelchair riders could only exit on the same side of the car they entered, as there was a pole blocking them from moving to the doors across the car. Those poles were removed and the floor patched shortly after delivery. Also, one of the things done when the rest of the fleet (PA-1 to -3) was rebuilt was to add controls to selectively operate some of the doors on the PA-4's. You can see them under a screwed-down coverplate at the top of the conductor's panel on the PA-1's to -3's - look for 2 sets of N / C / F labels (Near / Center / Far door controls for the front and back of the train). That's the one of the original reasons why trains had PA-4's at the ends.]

Presumably they learned their lesson from both of these - the PA-5's don't have the troublesome poles, and there is no intent to retrofit the rest of the fleet to interoperate with them.

Back to the seating question - the seating capacity should be similar between the PA-4 and -5. I'm surprised they didn't add auto fold-up seats at the ends of the car for wheelchair passengers. Perhaps they feel that the conductor's area (in the 5 or 6 cars where the conductor doesn't operate) would be sufficient. That does cut the choices down on the overnight service, as the 33RD train changes ends at HOB before continuing to Journal Square. So that leaves 3 out of 7 cars w/ one spot each.

A very long time ago, the seats were lateral and padded instead of the current longitudinal un-padded ones. They switched the layout to accomodate more standing passengers, and the pads left because they were getting vandalized. The first re-do had hard inserts installed where the pads were, while later ones just have the differently-painted part of the seat to remind passengers that they were once more comfortable. I expect that lateral seats were used to show another "modernization" from the last H&M K cars (12xx series), which had longitudinal padded benches, with the padding being continuous and not per-seat.

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Re: PATH signal system/tunnels

Post by OportRailfan »

Terry Kennedy wrote: I should mention that there is at least one exception to the "bottom left / top right" interlocking signal rule. The one that governs whether you go to HOB or Pavonia/Newport when you get to the NJ end of Tunnel A is an oddball for some reason. It has a [L][R] lightbox next to it to explain what it is trying to say. :-)
Isn't there also that one oddball as you come into Journal square from Newark. Its right after I think signal 730Z. Isn't the normal convention is reversed?
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Re: PATH signal system/tunnels

Post by R36 Combine Coach »

Terry Kennedy wrote:The PA-4's (the previous series, from the mid-80's) also had 3 sets of doors. [And poorer planning - wheelchair riders could only exit on the same side of the car they entered, as there was a pole blocking them from moving to the doors across the car. Those poles were removed and the floor patched shortly after delivery. Also, one of the things done when the rest of the fleet (PA-1 to -3) was rebuilt was to add controls to selectively operate some of the doors on the PA-4's
When the PA1/PA2/PA3s were overhauled by MK in 1987, they also had some seats at the end removed for wheelchair/handicap space. All overhauled PA1/2/3 cars also received a "R" added to to numbers. It was a smart choice to overhaul the older cars to be compatible with the PA4s.
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Terry Kennedy
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Re: PATH signal system/tunnels

Post by Terry Kennedy »

R36 Combine Coach wrote:When the PA1/PA2/PA3s were overhauled by MK in 1987, they also had some seats at the end removed for wheelchair/handicap space.
What do you mean? The only space without seats is the conductor's area.
All overhauled PA1/2/3 cars also received a "R" added to to numbers. It was a smart choice to overhaul the older cars to be compatible with the PA4s.
Given the smallish size of the previous PATH car orders, it wouldn't have made sense to have the 95 PA-4's not interoperate - that would have only given 11 to 13 trains, depending on the number of cars.

On the other hand, if the PA knew that the rebuilt PA-1 to -3's would be rusting and corroding badly within 15 years and need to be replaced, and that they would never use the door control retrofit, they might have done things differently.

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Re: PATH signal system/tunnels

Post by OportRailfan »

Terry Kennedy wrote:
R36 Combine Coach wrote:When the PA1/PA2/PA3s were overhauled by MK in 1987, they also had some seats at the end removed for wheelchair/handicap space.
What do you mean? The only space without seats is the conductor's area.
Opposite the Conductor's area. It has a big metal grab iron in the shape of an L turned 90 degrees clockwise, IINM.
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nyrmetros
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Re: PATH signal system/tunnels

Post by nyrmetros »

The PATH tunnels absolutely do seem more cramped than the subway tunnels or even the LIRR east river tunnels. Might be an optical illusion though.

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Re: PATH signal system/tunnels

Post by Head-end View »

Train2, there used to be a chart of PATH signal aspects and definitions somewhere on the internet. Try Googling "PATH signals" or something like that. You might still find it. :-)

mrsam
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Re: PATH signal system/tunnels

Post by mrsam »

nyrmetros wrote:The PATH tunnels absolutely do seem more cramped than the subway tunnels or even the LIRR east river tunnels. Might be an optical illusion though.
I have a very, very dim recollection of reading something on the order of PATH tunnels being deliberately designed with very tight clearances, so that the running trains themselves circulate the air in the tunnels by pushing it around.

Before 9/11 I commuted to/from Exchange place. While waiting for my train to Hoboken, I could tell that a train was coming long before I saw the headlights, by all the air rushing out of the tunnel. It got rather windy there.

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Re: PATH signal system/tunnels

Post by Terry Kennedy »

mrsam wrote:I have a very, very dim recollection of reading something on the order of PATH tunnels being deliberately designed with very tight clearances, so that the running trains themselves circulate the air in the tunnels by pushing it around.
I believe the air circulation quote was about the trains being in separate tunnels, rather than 2 tracks in one tunnel in the cut-and-cover parts (12th to 33rd). That's why the 14th and 23rd Street stations (and 19th and 28th when they were open) had a center wall between the tracks instead of being open.

The side walls of the tunnels have conduits for power and signals. Some of those needed to have parts chipped away for the PA-1 cars when those first went into service - the waistline bulge would have hit those parts. This is mostly around the Morton St. bend, since the track is very low in the tunnel there, which brings the widest spot of the waistline low enough to hit the conduits. This is also the reason that the single crossover west of 9th St. was taken up - the PA cars couldn't use it without hitting the iron casting of the tunnel wall.

Not all of the clearance issues have been resolved over the years. If you run a train in the opposite direction from normal coming into Grove St. from the east, and cross over to the normal direction, the train sway can hit the wall if you run at the maximum speed permitted by the signals.

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Re: PATH signal system/tunnels

Post by umtrr-author »

I'm by no means a PATH expert, so I'm wandering into dangerous territory here.

What I have observed in the case of approaching red signals at speed is that the trip arm connected with the signal goes down (out of "trip") position before the signal lights change from red to yellow or green. If I can see that from inside the car, then certainly the engineer can see them as well, and knows that the signal is about to change, so no need to slow down or stop. At least that's what I thought when I rode the PATH regularly, er, in the previous century.
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