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Thayer Viaduct



Photo taken by Ken Franke

BH Photo #106601


Street View 


Through truss bridge over the BNSF railroad and Two Mile Creek on MO 19/Business US 63 in Thayer
Oregon County, Missouri
Open to two-lane traffic
Future prospects
Scheduled for replacement in 2020; MoDOT accepting proposals for reuse until 12/31/2018
Built 1930 by M.S. Cartter & Co. of St. Louis
- M.S. Cartter & Co. of St. Louis, Missouri (Main span)
- Martin Wunderlich of Jefferson City, Missouri, and St. Paul, Minnesota (Substructure and approaches)
Main span: Pin-connected, 8-panel Pratt through truss
Approach: Two riveted, 6-panel Warren pony trusses
Length of largest span: 155.8 ft.
Total length: 305.0 ft.
Deck width: 20.0 ft.
Vertical clearance above deck: 15.3 ft.
Approximate latitude, longitude
+36.53327, -91.54846   (decimal degrees)
36°31'60" N, 91°32'54" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/629941/4044078 (zone/easting/northing)
Quadrangle map:
Land survey
T. 24 N., R. 5 W., Sec. 30
Average daily traffic (as of 2016)
Inventory numbers
MoDOT H-289A (Missouri Dept. of Transportation bridge number)
MONBI 4938 (Missouri bridge number on the National Bridge Inventory)
BH 22237 (Bridgehunter.com ID)
Inspection report (as of April 2016)
Overall condition: Fair
Superstructure condition rating: Fair (5 out of 9)
Substructure condition rating: Satisfactory (6 out of 9)
Deck condition rating: Fair (5 out of 9)
Sufficiency rating: 48.4 (out of 100)
View more at BridgeReports.com

Update Log 

  • September 14, 2016: Updated by Christopher Finigan: Added categories "Riveted", "Warren pony truss with alternating verticals"
  • September 13, 2016: New photos from Jack Schmidt
  • June 12, 2009: New photos from James Baughn
  • April 7, 2006: Posted photos from Ken Franke



Thayer Viaduct
Posted September 14, 2016, by James Baughn (webmaster [at] bridgehunter [dot] com)

According to Clayton Fraser's Missouri Historic Bridge Inventory, the main span on this bridge was financed and designed by the Frisco railroad. So it seems logical that they reused a truss from elsewhere.

I believe this is the only remaining pin-connected truss remaining on the Missouri state highway system.

Thayer Viaduct
Posted September 14, 2016, by Clark Vance (cvance [at] dogmail [dot] com)

The M.S. Cartter Company was built railroad bridges in the 1880s. There is a possibility that the trusses were reused from an older railroad bridge and relocated here.

Thayer Viaduct
Posted September 13, 2016, by Nathan Holth (webmaster [at] historicbridges [dot] org)

Through truss span shows evidence of being widened and the portal bracing totally replaced. And I assume the 1930 date is when this happened. The pin-connected trusses of course being older.

Thayer Viaduct
Posted April 4, 2006, by Ruth T. (ruthlt [at] yahoo [dot] com)

Nice bridges!