The '46 realignment shortened and straightened the line. The terrain is uneven in this area and the road was put through to connect several shorter roads when the county built the highway system in the Truman/Pendergast era. Noland Road made some turns here to move through some steep grades.
Looking at the old topos on HistoricAerials, it looks like they actually moved the railroad as opposed to straightening the road (no idea why they did this). Prior to the 1958 topo, the railroad crossed the road in the middle of the S-bend just north of here. I'm guessing that due to the lag in topo surveying that this was actually done in 1946 based on the build dates for this bridge and the highway overpass crossing the railroad on 56th Street just south of here. Bottom line, it looks like it's probably a just a cattle pass, though it probably does has a number in UP's book.
I looked at the area in a quadrangle map from landmarkhunter, and it appears that the bridge used to cross Noland Road, so "Old Noland Road Overpass" could be a name.
The old over pass is in the narrows, right in the S curve. If you look to the east, you can still see part of the old abutment, on the other side of the street is a house. You have to look quick, but it is there.