NJT signal indications

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ns3010
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NJT signal indications

Post by ns3010 » Tue Feb 24, 2009 2:02 pm

A few days ago, while passing over the tracks in Landing, one of the signal heads just to the east of Lake Hopatcong station was blinking green. What does this mean? The eastbound was not due into the station for a few more minutes.

Also regarding this signal, this morning, there was an eastbound departing the station and it had already passed the signal. None of the lights on any of the heads were lit, just like they would be if there was no train in the area.

Chessie GM50
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Re: Signal Question

Post by Chessie GM50 » Tue Feb 24, 2009 3:21 pm

ns3010 wrote:Also regarding this signal, this morning, there was an eastbound departing the station and it had already passed the signal. None of the lights on any of the heads were lit, just like they would be if there was no train in the area.
I believe that signals are on a timer to shut off, once a train has passed, and there isn't another in "x" amount of signal blocks.

You can find this info by a simple Google search.

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ns3010
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Re: Signal Question

Post by ns3010 » Tue Feb 24, 2009 3:55 pm

Chessie GM50 wrote:I believe that signals are on a timer to shut off, once a train has passed, and there isn't another in "x" amount of signal blocks.
Yes, I knew that. THe weird thing is that I could see the train just past the signal, so it should have been off.
Also, this was at 6:58am. There wasn't a train scheduled until 7:04 (872).

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Re: Signal Question

Post by ApproachMedium » Tue Feb 24, 2009 6:15 pm

ns3010 wrote:
Chessie GM50 wrote:I believe that signals are on a timer to shut off, once a train has passed, and there isn't another in "x" amount of signal blocks.
Yes, I knew that. THe weird thing is that I could see the train just past the signal, so it should have been off.
Also, this was at 6:58am. There wasn't a train scheduled until 7:04 (872).
Signals could have appeared off because they are focused to the engineers viewpoint. Scheduling has nothing to do with the signals, except that if your really earily, or really late, you may not get a controlled signal from the dispatcher, but thats another story.

Signals turning "on and off" is called approach lit signaling. Some parts of the railroad use 2 block method, some use single block. Which means if a train is in the block ahead of a signal, it will light up, once it clears the block the signal governs, it shuts off. In the 2 block method, it has to clear 2 blocks, and will light 2 blocks ahead etc...
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Re: Lake Hopatcong

Post by timz » Tue Feb 24, 2009 7:49 pm

If it really was showing flashing green, that has to mean "cab speed"? As if there were a turnout ahead good for 60 mph or more? So, is there such a thing east of the station?

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ns3010
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Re: Lake Hopatcong

Post by ns3010 » Tue Feb 24, 2009 8:24 pm

timz wrote:If it really was showing flashing green, that has to mean "cab speed"? As if there were a turnout ahead good for 60 mph or more? So, is there such a thing east of the station?
There is a double crossover east of the station. This particular train usually travels on the WB track from Port Morris to Lake Hopatcong. Upon departure, it crosses over to the EB track because a WB train is due in a few minutes, travelling on the WB track. So yes, there is a switch, and this particular train DOES change tracks.
ApproachMedium wrote:Signals could have appeared off because they are focused to the engineers viewpoint. Scheduling has nothing to do with the signals, except that if your really earily, or really late, you may not get a controlled signal from the dispatcher, but thats another story.
You can normally see the lights from the road, so that is out of the question. This train was 6 minutes ahead of scheduled departure. Te marker lights appeared to be a PL42, so I doubt that it was a freight. Or it could have been a non-revenue move, such as an x-train.

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Re: Signal Question

Post by Ken S. » Tue Feb 24, 2009 9:07 pm

I believe that a morning Boonton Line train originates at Denville.

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Re: Signal Question

Post by blockline4180 » Tue Feb 24, 2009 9:19 pm

Ken S. wrote:I believe that a morning Boonton Line train originates at Denville.

Why you are correct sir.
I also believe a Morristown Line train originated in Denville during the early 1980's under Conrail ownership, but I don;t know when that ended.
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Re: Signal Question

Post by PRRTechFan » Tue Feb 24, 2009 9:51 pm

To elaborate a little on ApproachMedium's explanation of approach-lit signals...

Approach lighting was originally devised to save energy and to extend the life of the signal lamps. When there was no train approaching the signal, there was no need to keep it illuminated. Many signal installations operated off of batteries that were constantly trickle-charged, so only lighting the signal when necessary resulted in less battery drain and a faster battery recharge.

On heavily traveled main lines, like the Northeast Corridor, signals were kept illuminated constantly because traffic was so frequent that the constant repetitive on-off-on-off operation of approach lighting would have actually resulted in greater wear on the relay contacts that switched the lamp power and would have not saved that much in energy or lamp life. I saw a PRR signal schematic that showed a scheme where signals were constantly lighted unless a loss of AC power caused a switch to battery operation. On battery only, the signals were approach lighted.

With approach lighting, the next signal is illuminated whenever the block before is occupied by a train. As soon as the signal "before" is passed, the next signal will light. If the block is very long or train speed is slow, the signal may light up well in advance of the train arriving. If the signal is near where the train originates it's run, the signal may illuminate as the train comes out of a yard or siding; or when it crosses from track to track in preparation for the return trip.

"What" the signal displays is not dependent on the train in the block "before" of it, but rather the condition and occupancy of the the track "beyond" it. The signal will display the appropriate aspect for the track beyond until the train just enters the block that the signal governs. This is usually less than an engine or coach length past the signal itself. As soon as the block the signal governs is entered, the signal will most likely always display all red: "stop" or "stop and proceed". With 1 block approach lighting, the signal will remain illuminated after the new block is occupied because the remainder of the train is still occupying the block "before". When the rear of the train finally passes the signal, the block "before" is no longer occupied and thus the approach lighting circuit darkens the signal.

Thus it is that the signal will illuminate in advance of the train and display whatever aspect is appropriate for the condition of the track ahead. When the first engine or cab car passes the signal, it will display all red; and as soon as the last car passes the signal, it will go dark.

What I have described is single block approach lighting. I have seen 2 block approach lighting, usually on track signalled in both directions. In this case, the signal heads remain illuminated whenever any part of the train occupies the block on either side of the signal.

As for a "flashing green", a flashing green on a single head or upper head of a multiple head signal does usually represent "cab speed". However, "cab speed" is an aspect that is usually associated with a more sophisticated ( I believe a "9 aspect") signal system that is added to or "overlayed" to the usual 4 aspect signal system. This is mainly done on higher speed lines; typically on the Northeast Corridor. Maybe some NJT Conductors or Engineers can chime in here... is "Cab Speed" typical on any NJT lines off of the NEC?

However, a flashing green on the lower head of a 2 head signal is usually associated with a "limited speed" aspect, either an "approach-limited" or a "limited-clear". These aspects are most likely associated with diverging routes over track switches that will allow the higher "limited" speed rather than the slower "medium" speed. The aspects are similar (red over green or yellow over green), but a steady green represents medium speed but a flashing green allows the higher limited speed.

I believe it was stated that there is a double crossover just past the signal in question. If these are limited speed turnouts and they were routed to change tracks, then a flashing-green "limited speed" aspect is most likely what was observed.

sixty-six

Re: Signal Question

Post by sixty-six » Tue Feb 24, 2009 10:20 pm

PRR,

I have never seen (although it doesnt mean that it doesnt exist) a cab speed signal outside the NEC.

I know some signals go off right away. The westbound interlocking signal at BANK on the west end of the platform goes off seconds after the hind end clears it.

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Re: NJT signal indications

Post by Tri-State Tom » Wed Feb 25, 2009 10:25 am

AM -
Signals turning "on and off" is called approach lit signaling. Some parts of the railroad use 2 block method, some use single block. Which means if a train is in the block ahead of a signal, it will light up, once it clears the block the signal governs, it shuts off. In the 2 block method, it has to clear 2 blocks, and will light 2 blocks ahead etc...
Where on NJT's system is the 2 block system used ?

Really informative signaling stuff here guys !!

thanks.

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Re: NJT signal indications

Post by sullivan1985 » Wed Feb 25, 2009 12:15 pm

ns3010 wrote:A few days ago, while passing over the tracks in Landing, one of the signal heads just to the east of Lake Hopatcong station was blinking green. What does this mean? The eastbound was not due into the station for a few more minutes.
What was the order of the targets?

Flashing Green over Red OR Red over a Flashing Green?

These are two very different signals.

ALSO, the train that passed, what track was it running on. Was it a run-through train or did it originate at Port Morris?
Ken S. wrote:I believe that a morning Boonton Line train originates at Denville.
For passengers. The equipment comes from Port Morris.
Tri-State Tom wrote:Where on NJT's system is the 2 block system used?
I think it's a good mixture depending on location. Automatic C86 and C87 at Rutherford are set up for 2-block. However, West BJ and Pascack Junction (the next signal in both direction from C86/C87) are set up to turn off AS SOON as the train clears its limits but light up one block before.

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Re: NJT signal indications

Post by NY&LB » Wed Feb 25, 2009 12:37 pm


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JoeRailRoad
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Re: NJT signal indications

Post by JoeRailRoad » Wed Feb 25, 2009 1:19 pm

Here's a link to the NORAC 9th Edition.
http://www.amtrakengineer.net/NORAC90408.pdf

And here is an excellent site on RR signals.
http://deltareum.com/signals.htm

Joe

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ns3010
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Re: NJT signal indications

Post by ns3010 » Wed Feb 25, 2009 1:21 pm

I can't seem to find this train (somewhere about 6:58) from Lake Hopatcong anywhere on the schedule. It DOES pick up passengers at LH, but I don't know where it originates, or which line it runs on.
This train, and EB to Hoboken, from what I have seen, travels on the Westbound track (leading me to believe that it originates at Port Morris). Upon leaving Lake Hopatcong, it crosses over to the Eastbound track, because a WB train pulls in a few minutes later. So yes, upon passing the signal, the train does change tracks.
I'm not sure exactly how these signals would be classified. Here's what they look like:


O O
O O

The bottom left head (green) was the one that was flashing. All of these signals are on one bridge spanning both tracks. The two heads to the right are placed above the EB track and the two to the left are above the WB track. Does each track have two signals governing that particular track, or is each head for a specific routing?

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