cab signal display question

[Anonymous]

Hi all,

I recently picked up what I am told is a PRR/PC/Conrail cab signal display unit cover, missing all the electric guts. My plan is to install lights and switches in it, to restore it to some semblance of working order, so I can manually control the output. I was hoping someone could help me label the controls properly.

It has 4 separate aspects:

x
x
x

--------

__x
_x
x

x
x
x

--------

__x
_x
x

--------

x
_x

--------

I am guessing they stand for Clear, Clear/proceed with caution, Proceed at reduced speed prepared to stop at next signal, and Stop, in that order. Can anyone confirm or correct my guesses? I'm also interested to learn where cab signals were/are used.

I am a relatively new railfan, and can use all the help I can get! :)

Carl

[Anonymous]

Much of the Norfolk Southern mainline between Cleveland, OH and Conway, PA (near Pittsburgh) uses cab signalling. The section on the Cleveland Line between Cleveland and Alliance, OH was completed in 2001-02. I'm not sure where else NS uses cab signalling, but I wouldn't be surprised if it's in use on other parts of the PRR mainline.

If you can find some documentation of PRR position light signal aspects, I think you'll have your other questions answered. Good luck with wiring your display!

Incidentally, my good friend Jerry Jordak is quite knowledgeable about position light signals and could probably offer a lot more help than I. He maintains an excellent Penn Central website at: http://pc.smellycat.com/

Scott Lothes
Cleveland, OH

[daveklepper]

I am giving you the benefit of my cab rides, mostly on the front platform of LIRR and PRR MP-54 commuter trains. This memory is about 30 years old, so others please forgive if there is a mistake . I see no absolute stop in the indications you have presented. That always was a horizontal display of three lights in the cab signal box. I will guess later why it is missing in yours! The top was an indication of track speed, clear track. The next was an indication that the next signal would be restrictive, either a block before a stop signal (stop and proceed permissive or absolute stop), or slow indication because of a diverging route. In high speed territory this would itself be a restrictive indication to start the slowdown process, say from 60 down to 35. It may have also been used for a high-speed diverging route. The next one down was the slow speed signal itself, usually if I remember, about 20 mph max. The bottom was a stop and proceed and not an absolute stop. Possibly in some cases the absolute stop was in a separate box with larger lenses and a larger overall indication, at the bottom of the vertical four position display, because I think I remember five position displays, not four, on the commuter cars I rode. Amtrak's own cab signal boxes were initially compatible with the PRR system. Do they have four displays or five? Some of you should have run these engines and seen these displays? Do the AEM-7's and Genesis locomotives have four or five? Dave.

PS: My first front platform ride was at the age 7 on a 1939 Worlds Fare - Penn Station non-stop. The LIRR advertized: Ten miles, Ten minutes, Ten Cents. It took twelve minutes. Still, a fast run. We had clear signals all the way until the approach to Penn Station, and when the first restrictive signal was passed the whistle/horn blew automatically in the tunnel, and the engineer and fireman were both most amused when I practically jumped out of my skin!

[DTomajko]

The former PRR mainline across Pennsylvania and the Northeast Corridor were and still are equipped with cab signals. On these lines according to FRA(?) regulations, a cab signal equipped locomotive must lead to operate at maximum track speed. All of NS's new engines are setup to lead on cab signalled lines as well as most all former Conrail engines. Also, CSX's former RF & P line south of Washington,DC is equipped with cab signals and for many years only RF & P engines would lead trains. By the way, the signal to the locomotive is transmitted through the rails to the locomotive, and the PRR and the RF & P used different frequencies to transmit data and their systems weren't interchangeable. Cab signal systems were used to increase train speeds and reduce train seperation on high traffic lines like the former PRR and I believe can't be discontinued without FRA approval, hence NS purchasing equipped locomotives.Also, I am not sure but I think that the CN & W line in Illinois is cab signal equipped and some other UP lines elsewhere. Good luck and stay safe.

[Rick Gates]

DATbeergeek From top on down they are: Clear Approach-Medium Aproach Restricting. Those are the 4 signal aspects on the Cab Signal cover you have found. Under old Penn Central rules, 1. Clear =Proceed (Golden Rail-slang) 2. Approach Medium=Proceed approach next signal at Medium speed (30mph) This could also correspond to an Approach Limited Wayside signal which means Proceed Aproach next signal at Limited speed (45mph) or depends on the length and speed of the turnout or crosover at the interlocking. 3. Approach=Proceed prepared to stop at next signal. Train exceeding Medium speed must at once reduce to that speed. 4. Restricting=Proceed at Restricted Speed. (Not exceeding 15mph, being prepared to stop for train, obstruction, or switch improperly aligned). There are other Wayside signals that could be encountered so these 4 are designed to give the lowest/safest possible speeds for all senarios.

[Rick Gates]

Forgot to include broken rail in the definition of Restricting Speed.

[daveklepper]

I gather that at some point the bottom indication, if my memory was correct and there indeed was the stop and stay stopped indication, was deleted and no signal at all was the replacement? Dave

[Rick Gates]

Dave- I have never heard or seen any "stop and stay stopped indication." I can't imagine the need for that one since your train owns the block ( once entered) and a restricting signal definition takes care of all other scenarios I can think of. The oldest rule book I have access to dates back to "50's on Pennsy cab signal territory. No mention of that one.

[daveklepper]

Do you happen to also have an LIRR rule book or a PRR book pre-WWII? Dave

[CSSHEGEWISCH]

Penn Central Rules for Conducting Transportation included cab signal aspects along with various corresponding wayside signal aspects and indications.