Wabash & Erie Canal Aqueduct over Aboit Creek in Allen County, IN

(Satellite, it looks like the abutments have fallen into the water)

Canal Society of Indiana posted
In the 1830s, engineers on Indiana canals used two styles of aqueducts. Like the Romans they built stone piers on a solid foundation of either bedrock or on a platform of long timbers. On top of the piers a flume made of timber and lined with planks was built to create a watertight box to conduct the canal waters across a stream or river. This first type of aqueduct is called an Open Trunk Aqueduct. The attached drawing shows this style at the Aboite creek crossing in Allen County.

Dennis DeBruler commented on the post
Was the route of the "Old Railroad Grade" on this map actually the route of the canal?
1961 Arcola Quadrangle @ 1:24,000
Canal Society of Indiana: Dennis DeBruler No the canal ran behind the Scout Center along Eagle Marsh - Towpath Trail etc. The Interurban ran on the old towpath.
[They must have misunderstood the question. But they answer why the cartographer thought it was an abandoned railroad --- the canal route was reused by an interurban railroad.]

Satellite plus Paint