There is great evidence of a bridge to the west of the current ford. I don't know how long ago the bridge "vanished"*. The current location of the ford makes sense, as that is where the river is fairly wide. During some winter melts (or heavy rainfall), the current ford is dangerous to cross (like last year) due to high water. The ford seems to have been somewhat improved, in that it is "fairly" flat via the rocks that make its base. There are a few "deeper" areas within the ford.
I have been across the ford several times over the last few years via ATV. I wish the bridge was still there.
Going with John's pictures, I have to say, that going up the switchbacks from the river (to the south, roughly) does provide some great locations to shoot the train. I found that out for my first time last year. Such as what I shot last year on video (see at about 4:12):
Youtube video from 2018
*There is a path going west from the ford to the location of the missing bridge on both sides of Los Pinos.