Hello, Jeremy. Is this interest for the sake of just personal curiosity or are you trying something like building a model-railroad layout of the line? if you go to the Blue Comet
website, there's an assortment of mid-to-late 1970s photos of those stations. At least with Bing or Google Maps you can follow the line and get a pretty good idea of where the surviving stations are.
As for precise locations of automatic block signals, unless you can somehow luck into pre-1981 railroad documents I'm afraid you're out of luck. I might recommend contacting the RCT&HS, but their archives have been mainly inaccessible to outside researchers for long enough that I wouldn't hold out a lot of hope. The kind of data you're looking for is almost certainly not online.
SEPTA still owns almost all of the Bethlehem Branch, but unlike some other commuter railroads or mainline freight railroads, copies of their employee timetables or other internal engineering documents are not available at train shows or railfan swap-meets or other informal sources for fans. That closes off the other possible major avenue of discovery.
Almost all of the masts which once held the block signals (even if the heads are vandalized or just removed entirely) are still standing north of the electrification's end at Lansdale, going as far north as the Lehigh/Bucks County line. Beyond that point, all are slated for removal as part of the "so-stupid-it-hurts" hike-and-bike trail that's being put in where the railroad once was.
Franklin Gowen • • • • READING COMPANY forum moderator
for "America's Largest Anthracite Hauler"!
In 2020, the late, great RDG overlaps with SEPTA, NS, CSX, RBM&N, and several shortlines - that's life . . .