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How to read LIRR Position light signals?


lilbluefoxie

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Posted

Are the LIRR signals the same as the PRR ones? Ive found a page with the info on the PRR ones, but Ive heard the LIRR has slight differences.

 

Also anyone know how to read the manual block signals on the Greenport Branch. The two color red and yellow light ones.

 

mattituck10.jpg


Posted

The colors on the Manual Block signals don't change. It was supposed to be that yellow would be adjacent to the track and red would be the further side from the track. I'm sure there's a more technical reason that I'm missing.

 

I think the LIRR position signals are very similar to the PRR styles, maybe a few variations on an aspect or two.

Posted
The colors on the Manual Block signals don't change. It was supposed to be that yellow would be adjacent to the track and red would be the further side from the track. I'm sure there's a more technical reason that I'm missing.

 

I think the LIRR position signals are very similar to the PRR styles, maybe a few variations on an aspect or two.

 

So if its Yellow you were to proceed straight, and if its Red you would proceed onto the diverging track

Posted

No, the lights don't change, they don't mean anything about what to do. They're just to show what track the block limit applies to. Block limits only apply to mainline tracks not the sidings. So if you had 2 tracks next to each other with a block limit sign between them, you could tell which track the signal applied to by seeing what side the yellow was adjacent to. MNR does the same thing but with out lights just colored reflectorized signs. The lights are for "night signals." Illuminated railroad signals were originally only used at night.

Posted
No, the lights don't change, they don't mean anything about what to do. They're just to show what track the block limit applies to. Block limits only apply to mainline tracks not the sidings. So if you had 2 tracks next to each other with a block limit sign between them, you could tell which track the signal applied to by seeing what side the yellow was adjacent to. MNR does the same thing but with out lights just colored reflectorized signs. The lights are for "night signals." Illuminated railroad signals were originally only used at night.

 

So when a train approaches that block limit thing, what do they usually do? Im kinda unfamiliar with manual block concepts.

Posted

Well, that depends on the movement authority that they're given on paper by the RTC or dispatcher. It can be: proceed, stop, stop on mainline for a meet or go into siding for meet(That's not the terminology). The concept of manual block is rather simple, but the rules are quite extensive.

Posted

There was once a site explaining the signal positions and meanings, but it probably went down years ago judging from when I tried to access it only to get a "404 not found" page.

Posted
There was once a site explaining the signal positions and meanings, but it probably went down years ago judging from when I tried to access it only to get a "404 not found" page.

 

whats the URL, it might be stored in teh web archive http://archive.org

Posted

the only thing im still unsure of is, how does it tell you which track you are going down. With the NYCT Signals, the second set of lights tell you if youre going on the main track or the diverging one.

Posted
the only thing im still unsure of is, how does it tell you which track you are going down. With the NYCT Signals, the second set of lights tell you if youre going on the main track or the diverging one.

 

PL's are a form of speed signalling, not route signalling.

Posted
PL's are a form of speed signalling, not route signalling.

 

so how do they know if they are going to be on the right track or not, coming out of jamaica, or valley stream for example?

Posted

Here are a few more links that may be helpful:

 

Railroad Facts and Figures - PRR Signals <--- Based on the 1968 PRR Rules

 

SEPTA Cab Signalling <--- Based on the original PRR system of four aspects (0, 75, 120, 180, all @ 100 Hz), which Metro-North still uses to this day. The LIRR's ASC system also uses the same 100 Hz carrier to deliver an additional two codes @ 270 ppm (60 mph) and 420 ppm (70 mph), and a speed display unit (SDU) is used rather than an aspect display unit (ADU). I know that this thread is about the PRR PL's, but I felt that this was pertinent.

 

NORAC Signal Rules <--- PRR PL's included, and some aspects blink!

 

1956 PRR Signal Rules <--- Excellent interactive page with a drop down menu to chose a rule, read the description and view the respective aspect.

 

NORAC Signal Rules and Aspect Demonstrator <--- Read the directions below the demonstrator on how to use this page, and you'll understand the principle behind speed signalling based on track condition. Though the page uses the US&S Type TP-5 and TR-2 "V-Type" or "Tri-Light" signals that are still seen around parts of the present-day CSX, Amtrak and NS systems, the concept remains the same.

 

How to determine signal aspects, names, and indications <--- This uses the old New York Central signalling system, but read the whole page, use your imagination and intelligence just a little bit, and use the same concept for the PRR system. Try quizzing yourself with the above pages for the PRR signals, and you'll be surprised at how well you'll know and understand PL aspects and indications.

 

Good luck, and feel free to ask questions if you need further assistance. This forum and RAILROAD.NET (yes, I did see your thread over there :P) have a number of people with a wealth of knowledge on this topic, and most are very willing to offer their insight.

Posted

To answer some of foxies questions:

 

•The LIRR uses the same system as the former PRR. But except for west of Harold, approach limited (/ over flashing |), limited clear (- over flashing |), medium approach (- over flashing /), and advance approach (flashing /) aren't used. Absolute clear (flashing |) and absolute medium clear (flashing - over flashing |) are used only in the event of signal trouble to indicate clear to next interlocking.

 

•Diverging moves can be, but are not alwAys, indicated by medium clear (- over |) or a drop to 60mph over a high speed interlocking. Other lower speed signals will be displayed for slower diverging movements.

 

•Stop and proceed (- over a single light or solid red over flashing red) is in fact used, especially on automatic signals (mostly found between Jamaica and Penn and Babylon to Patchogue), but can be found anywhere in the system.

Posted
To answer some of foxies questions:

 

•The LIRR uses the same system as the former PRR. But except for west of Harold, approach limited (/ over flashing |), limited clear (- over flashing |), medium approach (- over flashing /), and advance approach (flashing /) aren't used. Absolute clear (flashing |) and absolute medium clear (flashing - over flashing |) are used only in the event of signal trouble to indicate clear to next interlocking.

 

•Diverging moves can be, but are not alwAys, indicated by medium clear (- over |) or a drop to 60mph over a high speed interlocking. Other lower speed signals will be displayed for slower diverging movements.

 

•Stop and proceed (- over a single light or solid red over flashing red) is in fact used, especially on automatic signals (mostly found between Jamaica and Penn and Babylon to Patchogue), but can be found anywhere in the system.

 

thanks for the info, so for stop and proceed, it just lights up the light in the center of the circle but none of the spokes?

Posted
thanks for the info, so for stop and proceed, it just lights up the light in the center of the circle but none of the spokes?

 

It looks like this:

 

ussppl1.gif

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