BNSF Mendota Subdivision Bridge
Looking West through the 60' BNSF Mendota subdivision bridge. The Aurora Subdivision tunnel is beyond and the Lake St tunnel beyond that
Photo taken by Steve Conro in January 2012
BH Photo #224085
I agree that these are rigid frames or slabs on walls. I think the description below is a good one. If it is bored or cut through a formation it's a tunnel. If it has fill over it, its a bridge or culvert.
I use "tunnel" for cuts through existing formations, "bridge" (usually rigid frame) where it passes through fill built up over it.
I guess I would classify them as not much more than box culverts with wingwalls. They're basically the same design as those that are used to allow pedestrian and biking trails to pass under freeways, but on a larger scale.
I really don't know if these should be tunnels or bridges. Anyone care to weigh in. I'd be glad to change them.
Thanks everyone, bridges it is.