Rating:
3 votes

MRL - Clark Fork River Bridge #12

Photos 

Photo taken by Garrett Boon in April 2011

Enlarge

BH Photo #196927

Map 

Street View 

Description 

Information from NPRHA.org Online Collection

Facts 

Overview
Bridge over Clark Fork River on Montana RailLink
Location
Sanders County, Montana
Status
Open to traffic
History
Built 1908, Reinforced date unknown
Railroads
- Burlington Northern Railroad (BN)
- Montana Rail Link (MRL)
- Northern Pacific Railroad (NP)
Dimensions
Length of largest span: 150.0 ft.
Total length: 456.0 ft.
Deck width: 18.0 ft.
Approximate latitude, longitude
+47.32178, -114.89216   (decimal degrees)
47°19'18" N, 114°53'32" W   (degrees°minutes'seconds")
Approximate UTM coordinates
11/659281/5243077 (zone/easting/northing)
Quadrangle map:
Keystone Peak
Elevation
2566 ft. above sea level
Inventory number
BH 45430 (Bridgehunter.com ID)

Update Log 

  • February 8, 2020: Updated by John Marvig: Added information from NP bridge records
  • April 5, 2018: New photos from Richard Doody
  • March 21, 2018: Updated by John Marvig: Added Build Date from NP Bridge Book
  • June 2, 2017: Updated by Christopher Finigan: Added categories "Pin-connected", "Riveted"
  • October 8, 2013: Updated by Luke Harden: Added categories "Railroad", "Montana Rail Link"
  • April 8, 2011: New photos from Garrett Boon
  • May 31, 2010: Added by Craig Philpott

Sources 

Comments 

MRL - Clark Fork River Bridge No. 3
Posted August 20, 2015, by Nathan Holth (webmaster [at] historicbridges [dot] org)

Tim, its based off a patented supplemental arch system invented by Jai Kim as shown here http://www.google.com/patents/US4691399

MRL - Clark Fork River Bridge No. 3
Posted August 20, 2015, by Tim Nordstrom (tim [dot] nordstrom [at] comcast [dot] net)

Thanks for the photos.

It could be called a Pratt Deck Truss with Bow-String retro-fit.

Clark Fork Railroad Bridge #2
Posted October 8, 2013, by Jim Lueken (lueken [at] bellsouth [dot] net)

These 'supplemental' arch members were a very clever way to add strength and capacity to the original trusses while keeping the original members intact. Congrats to those reponsible!

Clark Fork Railroad Bridge #2
Posted April 9, 2011, by Anthony Dillon (spansaver [at] hotmail [dot] com)

Yup.....that's what I would call it Craig.

I wish the Madison Railroad in Southern Indiana would do this to their deck trusses instead of demolishing them.

Clark Fork Railroad Bridge #2
Posted April 8, 2011, by Craig Philpott (cphilpott [at] puc [dot] edu)

Interesting modification and mixture of forms. So now, what type of span is this? Pratt Thru Truss with supplemental Arch?

Clark Fork Railroad Bridge #2
Posted April 8, 2011, by Garrett Boon

You will notice some changes in the recent photos I took and the Google Stree View. They've been working on this bridge adding an arch in the truss.