Rating:
3 votes

Mile Load Road Bridge

Photos 

Side view, facing west

The deck truss is almost impossible to see from the deck.

Photo taken by Fmiser in July 2012

License: Creative Commons Attribution-Share-Alike (CC BY-SA)

Enlarge

BH Photo #234678

Map 

Facts 

Overview
Deck truss bridge over the BNSF Railroad on Mile Load Road (TR 42)
Location
Fulton County, Illinois
Status
Open to traffic, one lane, 10 ton weight limit
Railroad
- Chicago, Burlington & Quincy Railroad (CBQ)
Design
Pin connected pratt deck truss with timber floor beams and deck. North approach stringer is 70 ft long. South approach stringer is 40 ft long
Dimensions
Length of largest span: 100.0 ft.
Total length: 213.8 ft.
Deck width: 16.0 ft.
Approximate latitude, longitude
+40.35724, -90.22081   (decimal degrees)
40°21'26" N, 90°13'15" W   (degrees°minutes'seconds")
Approximate UTM coordinates
15/736005/4471116 (zone/easting/northing)
Quadrangle map:
Duncan Mills
Land survey
T. 4 N., R. 2 E., Sec. 1
Elevation
560 ft. above sea level
Average daily traffic (as of 2015)
50
Inventory numbers
IL 029-9908 (Illinois bridge number)
BH 15247 (Bridgehunter.com ID)
Inspection report (as of December 2018)
Overall condition: Poor
Superstructure condition rating: Fair (5 out of 9)
Substructure condition rating: Fair (5 out of 9)
Deck condition rating: Poor (4 out of 9)
Sufficiency rating: 32.2 (out of 100)
View more at BridgeReports.com

Update Log 

  • February 24, 2019: Updated by Clark Vance: Added category "Chicago, Burlington & Quincy Railroad"
  • July 7, 2012: Updated by Fmiser: Update design
  • July 7, 2012: Updated by Luke Harden: Edited map and bridge. Was improperly categorized as a pony truss

Sources 

  • Fmiser - fmiser [at] gmail [dot] com
  • Luke

Comments 

Mile Load Road Bridge
Posted February 24, 2019, by Clark Vance (cvance [at] dogmail [dot] com)

I'm not sure whether to make anything of this but the 1948 topo shows the kink in the road and a 562 benchmark. The 1925 maps shows a straight road and a 553 benchmark. This makes me think the current bridge went in during this time period on a slightly different alignment.

Mile Load Road Bridge
Posted February 23, 2019, by John Marvig (marvigj27 [at] gmail [dot] com)

Thanks Tony! I've been trying to identify such cases involving trusses and girders. They used to be everywhere, as spans not strong enough for railroad use found their way onto road overpasses, particularly on mainlines. Based on 1918 track profiles for Wisconsin, we've lost somewhere around 95% of the original population of these unique structures, and unfortunately these are often constructed of 1880s and 1890s pieces.

Mile Load Road Bridge
Posted February 23, 2019, by Tony Dillon (spansaver [at] hotmail [dot] com)

I think you're spot on John... Neat bridge!

Mile Load Road Bridge
Posted February 22, 2019, by John Marvig (marvigj27 [at] gmail [dot] com)

This bridge appears to be a rare deck truss example of a recycled railroad bridge reused on an overpass.

Mile Load Road Bridge
Posted July 7, 2012, by Fmiser (fmiser [at] gmail [dot] com)

I walked across the bridge twice and took a bunch of photos before I finally spotted evidence of a truss. And then it was a glimps through the trees. So I hiked down and around to get a view of the side and underside.

This is an odd bridge for automobiles. It feels more like a railroad bridge - so it makes sense it was built by the railroad.

Things I found odd about it:

- Narrow deck truss

- Timber bents and timber cribs substructure

- Timber floor beams

- Timber deck _without_ runners

- The approach spans are not in line with the main span. The south approach is pretty close, but the north approach is definitely not resulting in a curved appearance.

The deck has a very noticable dip in both approach spans. With it's listing as a truss, these dips made me very nervous! But the truss span is straight and level. It appears the bents under the approach spans have settled causing the dips.

The truss is pin connected, with 4 to 6 upset eye bars per panel. This seems heavy duty - but then the distance from the bottom chord to the top chord is only about 8 ft. (2.5 m) I think the short verticals means more tension on the bottom chord...

For future visitors, there is a road off of Mile Load Rd a bit south-east of the bridge that has a grade-level crossing of the railroad tracks. And keep an eye out, there's a lot of poison ivy.

Mile Load Road 42 Bridge
Posted November 19, 2009, by Dale Travis (daletravis [at] bigfoot [dot] com)

Photos taken 11-4-09.