I was kinda curious how long these PL signals measure, so I think I found answers for the measurement of these Pennsy signals in this "standard plan" blueprint (printed circa 1952) on the top very left here: http://prr.railfan.net/signalstanda...401-F&frame=YES&sortdir=up&sortby=8&rr=pennsy . Are the measurements correct or what? :tb-biggrin:
I would say the drawing is correct. It appears to be a component layout for the signals, something a manufacturer would use. The 7-3/4" roundels are correct.
I'm sure the drawings (S-400-F, -401-F) are correct, and correspond to field use on masts (as illustrated) or multi-signal mountings. Some installations with limited aspects, eliminated the "background" on the lower arm, using only the lights and connecting conduit - something I would find difficult to model in HO or smaller scale. Don't know what CSX is doing, but NS is replacing these signals, as they come up for maintenance or refurbishment, with Color Lights on new masts and cantilever/bridge supports...take pics, if you see 'em! Bob C.
