I'm not 100% sold, but enough so that it's not worth disagreeing anymore.
Personally, I look at this as an attempt to preserve historical accuracy, not a debate on who is right or wrong. If info shows my guesses are incorrect I take no offense whatever, I'm happy that we get it right. So if someone has doubts, don't be afraid to say so. This isn't bickering, it's research.
A couple "for what it's worth" observations: First, I'm convinced the train is moving, not standing. The photographer's father looks like he has just taken a shot as the train approached him, and now has lowered the camera and started to walk away.
By the way - obviously there is ANOTHER pic taken at this location, by the father. Wonder if it is available - maybe a view in the opposite direction would have detail to pinpoint where it is.
Also, blowing up the first pic and counting rail joints, from the engine to the start of the curve I get somewhere about 22 to 25 or even 30 - hard to say exactly. Those would be 39 foot rail so the train is ballpark 900 to 1000 feet from the curve. That's over 3 football fields, and the bridge itself is probably that far again once you leave the tangent. So altho my eye sees the train and bridge as close to each other, the train is probably a good half mile from the bridge. Maybe this will help when comparing signal locations and bridges.
Merry Christmas to y'all!