Well Bret, I don't think the bridge over the river was three railed until the old main line to baker was torn out. This photo from the 1930's shows the bridge track departing from part of the S Baker wye. Both of these tracks were removed when the 3-rail crossing was put in. The Sanborn maps don't differentiate between 2-rail and 3-rail.
This pic was taken from almost the same angle as the first, but from a little further back. The train is on the main track, which is the nearest one in the first photo in this thread.
The consist of the train is the same as the last passenger (mixed) train, but the photo is not identified as such.