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B Avenue Overpass

Tama County, Iowa

Photos 

The west face

This bridge is a typical pony truss built by the Chicago & Northwestern Railway in Iowa in the early part of the 20th Century. (The C&NW was absorbed by the Union Pacific in 1995.)

Photo taken by J.R. Manning in July 2007

BH Photo #109897

Map 

Description 

This truss is typical of a Chicago & North Western Railway built overpass. These overpasses used rebuilt railroad spans, such as this one.

Facts 

Overview
Pony truss bridge over Union Pacific Railroad on B Avenue
Location
Tama County, Iowa
Status
Open to traffic
History
Built ca. 1920
Railroad
- Chicago & North Western Railway (CNW)
Design
Riveted double-intersection Warren pony truss
Dimensions
Length of largest span: 79.1 ft.
Total length: 136.2 ft.
Deck width: 18.0 ft.
Also called
C&NW Bridge #423 1/2
Approximate latitude, longitude
+41.99101, -92.74626   (decimal degrees)
41°59'28" N, 92°44'47" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/521017/4648808 (zone/easting/northing)
Quadrangle map:
Montour
Land survey
T. 83 N., R. 16 W., Sec. 20
Average daily traffic (as of 2001)
25
Inventory numbers
IA 318380 (Iowa bridge number)
BH 14492 (Bridgehunter.com ID)
Inspection report (as of September 2008)
Overall condition: Poor
Superstructure condition rating: Poor (4 out of 9)
Substructure condition rating: Poor (4 out of 9)
Deck condition rating: Poor (4 out of 9)
Sufficiency rating: 31 (out of 100)
View more at BridgeReports.com

Categories 

Chicago & North Western Railway (1,404)
Double-intersection Warren pony truss (202)
Double-intersection Warren truss (456)
Iowa (6,499)
Modified (38)
One-lane traffic (7,606)
Open (39,882)
Owned by county (20,783)
Pony truss (16,184)
 Rail-to-overpass (61)
Rebuilt (3)
Relocated (890)
Riveted (2,165)
Span length 75-100 feet (6,428)
Tama County, Iowa (102)
Total length 125-175 feet (5,920)
Truss (32,782)
Wooden deck (6,069)

Update Log 

  • January 3, 2019: New photos from John Marvig
  • January 26, 2008: New photo from J.R. Manning

Sources 

  • J.R. Manning - thekitchenguy [at] sbcglobal [dot] net
  • John Marvig - marvigj27 [at] gmail [dot] com
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Comments 

B Avenue Overpass
Posted January 3, 2019, by John Marvig

Even a small truss like this could be narrowed down and reused for a trail or light vehicle crossing. It would add a lot more charecter to American parks and green spaces.

B Avenue Overpass
Posted January 3, 2019, by Clark Vance (cvance [at] dogmail [dot] com)

Counties could learn about reuse from the money-conscious railroad companies. We'd have a lot more preserved road trusses if they moved them to lesser roads when they need to be replaced.

B Avenue Overpass
Posted January 3, 2019, by John Marvig (marvigj27 [at] gmail [dot] com)

This bridge appears to be another example of a pony truss that was originally built ca. 1885 as a railroad bridge, and later reconstructed with a new floor to serve as a railroad overpass. The bridge did not show up in a 1917 inventory of railroad structures, indicating a post-1917 date.