Number Boards on PRR Signals

[nscaleSPF2]

Does anyone know what the numbers on these signals represented?  Were they mile markers, block numbers, or just sequential numbers?  I did some research, but was not able to find the answer.

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[Missaberoad]

Milage down to the tenth of the mile.
That signal should be at mile 107.1 of its subdivision.

[C855B]

I don't know Pennsy's rulebook, but be aware that on many RRs, presence of a number board influenced how the aspect was to be interpreted.

[eric220]

I don't know Pennsy's rulebook, but be aware that on many RRs, presence of a number board influenced how the aspect was to be interpreted.

This is true. If memory serves, the number boards designate the signal as an automatic intermediate signal (as opposed to a CTC dispatcher controlled signal).

[Missaberoad]

http://www.railroad-line.com/forum/data/INRAIL/201111221566_ConrailSignalAspects.JPG

Here's a conrail era chart showing how the presence of a numberboard modifies the indication.

An addition to my original comment signals that are side by side usually have different milages (usually by .1 of a mile) so crews can differentiate.

http://photos.wikimapia.org/p/00/01/15/67/15_big.jpg

[jmlaboda]

An addition to my original comment signals that are side by side usually have different milages (usually by .1 of a mile) so crews can differentiate.

I would suspect that in this case the "1", "2" and "3" are not .1 of a mile but rather track numbers, Track 1, Track 2 and Track 3 at mile 227.

[Missaberoad]

I would suspect that in this case the "1", "2" and "3" are not .1 of a mile but rather track numbers, Track 1, Track 2 and Track 3 at mile 227.

Possibly, but the same numbering system occurs on opposing signals on single track at the same location when the E and W suffex aren't used.

Mind you my knowlege is CROR and it seems signal standards are all over the place

[nscaleSPF2]

Thanks, guys, for the information.  You are the best.

the number boards designate the signal as an automatic intermediate signal (as opposed to a CTC dispatcher controlled signal).

This confirms what I found in my search.

[cv_acr]

Possibly, but the same numbering system occurs on opposing signals on single track at the same location when the E and W suffex aren't used.

Note that typical standard practices are:

1) signal nos. based on mileage, to nearest tenth of a mile (as stated)
2) odd nos. ONLY in one direction and even nos. ONLY in the other
3) always count up

So for example, intermediate block signals at the same place facing opposite directions on single track would be numbered 301/302 if location somewhere approximately around mile 30.1-30.2

4) With multiple tracks, add on additional letters/etc. to designate tracks, i.e. N, S, E, W, or -1, -2, -3, etc. A, B etc. is also common on certain roads for dwarf/other signals exiting sidings.

(I don't think there are actually any RULES for numbering signals, just typical practices, so YMMV depending on railroad.)

Mind you my knowlege is CROR and it seems signal standards are all over the place

I don't know Pennsy's rulebook, but be aware that on many RRs, presence of a number board influenced how the aspect was to be interpreted.

This is true. If memory serves, the number boards designate the signal as an automatic intermediate signal (as opposed to a CTC dispatcher controlled signal).

I believe this to be true on most if not all major US railroads including PRR, and it's what's always repeated in most signaling explanations in the model/railfan press and online, but it's decidedly NOT true in Canadian rulebooks. Presence/absence of the number plate had no rules meaning on Canadian railways, and pretty much all signals north of the border have plates.

Some rulebooks may differ, so YMMV.