I just bought the PRR signal bridge and was wondering if this is to scale. It took me about 4 hours to build and I’m very happy with how sharp it looks built up. However when I placed 4 tracks inside the bridge, the spacing seems a little tight. How many inches should the tracks be separated on the layout?
Edit: Almost forgot another crucial question, what should the height difference be between the track and the signal masts. On plywood if the tracks are laid flat, there seems to be more than enough clearance, however if I were to lay the track on cork, it would seem to be cutting it close between the top of the engine and the bottom tip of the signal mast. They are nowhere near touching, just unsightly when the track is raised on roadbed.
Also, do you know where I can get the right size amber bulbs to light the tower and where exactly should the targets be placed? I copied the box example.
Here is what it looks like:
Why are the signals placed like this if there are 4 tacks, just curious.
Signal heads were normally (not always) mounted so that they could be seen by the engineer of an approaching train. Those bridges could have signals mounted on both sides if the track was bi-directional. Here is a link to a former PRR signal bridge. If you look closely, you will see that there are signals mounted on both sides: http://www.flickr.com/photos/vxla/4547917847/
What is your track spacing? It could be the bridge is designed for a scale spacing of 13 foot center to center but your track spacing is 20 foot. The mast should not hang below the lowest part of the bridge. Also check Oregon rail and NJ international for working PRR position signals.
13 feet scales out about 1 3/4 inch. This is measured at the center between the rails of one track to the next. This is for straight track. Curves should be wider. NMRA Recommendation S-8 is wider then scale. About 20 scale feet. This is to give us a little finger room to rerail. If your 4 track signal bridge is scale then the four tracks are going to be too wide for the bridge. It would probably be a better fit with a two track main with a passing siding either on one side or the middle. Maybe you could widen the bridge with another bridge. Things like this is why we have to deal with compromises and compression in the hobby. It is impossible to scale my fingers to 1/87.
Yeah, the biggest problem I had was getting my fingers in there, everything seems to tight, and I can’t imagine curves being that close together. I think I’ll go for the 2 track main with the siding, thanks you’ve been a great help.
On the prototype there is only a few inches between cars on double track. Curves are wide enough for clearance. On our model railroads we have to widen the gap between tracks for overhanging cars and locomotives unless you have room for 10 foot radius curves. Most of us modelers have 2 inch track centers and go 2 to 21/2 on curves. This is beyond the NMRA recommendation but is a convenience for us.
“Edit: Almost forgot another crucial question, what should the height difference be between the track and the signal masts. On plywood if the tracks are laid flat, there seems to be more than enough clearance, however if I were to lay the track on cork, it would seem to be cutting it close between the top of the engine and the bottom tip of the signal mast. They are nowhere near touching, just unsightly when the track is raised on roadbed.”
Signals - and signal bridges - are usually mounted on ballasted pads about the same height as the track roadbed. In other words, mount the bases on (ballasted) cork pads, beside the track’s cork.
