2 votes

CN - Boyer River Bridge (Near Denison)


CN Boyer River Bridge #4


Photo taken by John Marvig in October 2015


BH Photo #339852

Street View 


Pratt Through truss bridge over Boyer River on Canadian National Railway
Denison, Crawford County, Iowa
Open to traffic
Built 1899, Piers Rebuilt 1948
- American Bridge Works of Chicago, Illinois
- Canadian National Railway (CN)
- Chicago, Central & Pacific Railroad (CC)
Pratt through truss
Length of largest span: 126.0 ft.
Total length: 250.0 ft.
Approximate latitude, longitude
+41.98181, -95.41287   (decimal degrees)
41°58'55" N, 95°24'46" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/300108/4650572 (zone/easting/northing)
Quadrangle map:
Dow City
Inventory number
BH 51385 (Bridgehunter.com ID)

Update Log 

  • October 19, 2015: New photos from John Marvig
  • October 18, 2015: Updated by John Marvig: Added information
  • October 16, 2015: Updated by Luke: Added category "American Bridge Works" per field check from John
  • October 14, 2012: Updated by Luke Harden: Corrected name & railroad
  • February 23, 2012: Updated by Luke Harden: Added category "Iowa Northern Railroad, Changed minor details: the railroad in the Iowa Northern Rai
  • February 22, 2012: Updated by Daniel Hopkins: Added category "Railroad"
  • February 22, 2012: Added by Jason Smith


  • Jason Smith - flensburg [dot] bridgehunter [dot] av [at] googlemail [dot] com
  • Luke
  • John Marvig - marvigj27 [at] gmail [dot] com


CN - Boyer River Bridge (Near Denison)
Posted January 24, 2019, by John Marvig (marvigj27 [at] gmail [dot] com)

While attempting (unsuccessfully) to find information about the numerous girders along this route, I found that this bridge (Denison) was not in place in 1944. However, it was in place in 1973, and the substructures were dated 1948. About 50 miles west, I came across a bridge with similar dimensions that was replaced in 1947 (Ascot). It seems that Ascot is the most likely location it could have originally been constructed. I have attached the 1944 and 1973 track charts for each bridge. My question about the truss is, would it have been possible for the truss to be shortened by two feet upon relocation?

Also, I cannot be certain that this was the original location of the approach girders. Several crossings of the Boyer River were filled in around the same time, and there are a few other 45' through girders that were relocated through the 40s, 50s and 60s along the route with identical structural details. This route was constructed between 1899 and 1900.