This information is very helpful. The info I posted earlier was obtained from the current owner of the bridge, Tommy Bolack. However, I'm inclined to believe the AFEs from Jimmy and also info from ROW Explorer. This bridge looks identical to bridge 485B, however, MP 485.58 is painted on it although it came from Cedar Hill which was MP 472.32.
I think I need to go visit the owner and take another look at the bridge. If I get new info I will post it here. Many thanks for all the comments posted so far. BTW, Tommy welcomes anyone interested to come over and take a look at the bridge. Just call the B Square ranch.