4 votes

CP - Rock River Bridges (Byron)


Photo taken by Steve Conro in November 2011


BH Photo #221210



Two very interesting bridges crossing the Rock River here. Separate spans, but share a substructure.

The Westbound Spans (Northern Spans) consist of 5 Riveted Warren Through Truss spans with all verticals. Each are 8 panels long, and the western four spans have vertical endposts at the northeast end. Their lengths are as follows, from West to East: 170', 160', 165', 165' and 160' for a total length of 820 Feet. These spans rest on stone substructures, capped with cement. The bridge contains an early version of punch plate members and A-Frame Portal, which suggest it may have been built in the 1930s to replace an older bridge. They are still in use.

The Eastbound Spans (Southern Spans) consist of 5 late construction Pin Connected Pratt Through Truss spans with a heavy skew. These trusses have 6 panels each, and contain the following lengths: 155' and 165' with the eastern three being 160' each. The total length of these spans is 800 Feet. These spans rest on all concrete substructures, and were built in 1905 by the Chicago Bridge & Iron Company when the CMStP double tracked this line. This span is no longer in use.

The area was once called "Loose Pulley Junction", after a former engineer who lived near the east end of this bridge. The ghost piers downstream are from the earlier bridge. It is unknown when this bridge was built on this alignment, however it was well before 1905.


Twin Through Truss bridges over Rock River on Canadian Pacific Railway
Byron, Ogle County, Illinois
Open to traffic
Southern Spans Built 1905
- Chicago Bridge & Iron Co. of Chicago, Illinois
- Canadian Pacific Railway (CP)
- Chicago, Milwaukee, St. Paul & Pacific Railroad (MILW)
- Dakota, Minnesota, & Eastern Railroad (DME)
Twin parallel 5 span through truss bridges. Slightly offset due to angle of river, with the south span being no longer in use. The northern spans are riveted Warren through trusses, and the southern are pin connected Pratt through trusses
Length of largest span: 170.0 ft.
Total length: 820.0 ft.
Approximate latitude, longitude
+42.12779, -89.23201   (decimal degrees)
42°07'40" N, 89°13'55" W   (degrees°minutes'seconds")
Approximate UTM coordinates
16/315515/4666376 (zone/easting/northing)
Quadrangle map:
Land survey
T. 25 N., R 11 E., Sec. 33
680 ft. above sea level
Inventory number
BH 49910 (Bridgehunter.com ID)

Update Log 

  • March 30, 2015: Updated by John Marvig: Added information
  • June 29, 2012: Photo imported by Luke Harden
  • March 12, 2012: Updated by Luke Harden: Added category "Canadian Pacific Railway"
  • March 12, 2012: Updated by Steve Conro: Added category "Chicago, Milwaukee, St. Paul & Pacific Railroad"
  • December 11, 2011: Updated by Clark Vance: Added PLSS info
  • December 10, 2011: Updated by J.P.: updated design
  • October 25, 2011: Added by Steve Conro

Related Bridges 



DM&E Rock River Bridges - Byron2
Posted March 15, 2012, by Steve Conro (sconro [at] yahoo [dot] com)

And I knew that. Got my National and Pacific mixed up, thanks for the catch.

DM&E Rock River Bridges - Byron2
Posted March 12, 2012, by Luke Harden (lmharden [at] iastate [dot] edu)

Steve, the CN does not control the DM&E, the Canadian Pacific does.