3 votes

UP - Zoo Truss


West Elevation

This bridge crosses an abandoned rail right-of-way that was once Milwaukee Road trackage. It carries the Union Pacific on a major route for the railroad. The bridge was built by the Chicago & Northwestern Railway, probably in the late 19th century.

The bridge is located in West Allis, Wisconsin, in western Milwaukee County. It is just south of I-94, across from the Milwaukee County Zoo and within 300 yards of the Zoo Interchange.

Photo taken by J.R. Manning in November 2009


BH Photo #149648

Street View 


Quadrangular Warren through truss bridge over Hank Aaron State Trail on Union Pacific Railroad
West Allis, Milwaukee County, Wisconsin
Intact but closed to all traffic
Built 1910, Bypassed and left standing 2015
- Cleary-White Construction Co. of Chicago, Illinois (Substructure)
- Pennsylvania Steel Co. of Steelton, Pennsylvania
- Chicago & North Western Railway (CNW)
- Chicago, Milwaukee, St. Paul & Pacific Railroad (MILW)
- Milwaukee, Sparta & Northwestern Railway (MS&NW)
- Union Pacific Railroad (UP)
Quadrangular Warren through truss
Span length: 175.0 ft.
Total length: 175.0 ft.
Approximate latitude, longitude
+43.02700, -88.04511   (decimal degrees)
43°01'37" N, 88°02'42" W   (degrees°minutes'seconds")
Approximate UTM coordinates
16/414851/4764343 (zone/easting/northing)
Quadrangle map:
Inventory number
BH 43655 (Bridgehunter.com ID)

Update Log 

  • October 27, 2021: New photo from Mark Boettcher
  • August 10, 2015: Updated by John Marvig: Updated status, bridge is closed but preserved in place
  • August 9, 2014: Photo imported by Dave King
  • June 14, 2014: New photos from John Marvig
  • June 6, 2014: Updated by John Marvig: Added information
  • March 28, 2014: Updated by Matt Lohry: Corrected status--still in service, but new bridge is under construction
  • January 29, 2014: Updated by Matt Lohry: Updated status: this bridge is now doomed.
  • October 28, 2012: Updated by Luke Harden: Added builder & build date.
  • October 28, 2012: Updated by Matt Lohry: Updated facility crossed--the abandoned right-of-way is now the Hank Aaron State Trail
  • October 19, 2010: Updated by Matthew Lohry: Updated bridge type
  • July 21, 2010: New photos from Nick Brnot
  • July 15, 2010: New Street View added by Nick Brnot
  • November 22, 2009: Added by J.R. Manning


  • J.R. Manning - thekitchenguy [at] sbcglobal [dot] net
  • Matt Lohry
  • Historicbridges.org - by Nathan Holth
  • Luke
  • John Marvig - marvigj27 [at] gmail [dot] com
  • Mark Boettcher


UP - Zoo Truss
Posted August 10, 2015, by Jason Smith (flensburg [dot] bridgehunter [dot] av [at] googlemail [dot] com)

Any idea of whether the bridge will become a bike trail?

UP - Zoo Truss
Posted August 10, 2015, by Dave King (DKinghawkfan [at] hotmail [dot] com)

I was informed last night that this bridge will be saved and remain where it is. A Panoramio user told me he spoke with WIDOT workers at the State Fair and they told him that the bridge has historical significance and will not be demolished.

UP - Zoo Truss
Posted June 20, 2015, by John Marvig

I drove through Milwaukee on my way to Chicago. The bridge is still fully intact, with the area regraded and reseeded. I did not see if the bridge is really going to serve as anything, but it wasn't fenced off, and I figure if it was to be demolished, they wouldn't have reseeded it. Has anyone seen or heard anything more?

UP - Zoo Truss
Posted March 27, 2015, by John Marvig (marvigj27 [at] gmail [dot] com)

Awesome! I'm actually in Rockford, Illinois this weekend, but I wish I could see the structure currently.

It's a good step. I found documents obline several months ago stating that bridge is significant in the light that it reinvented the type of truss (quadrangler lattice). Will post when back on home computer.

UP - Zoo Truss
Posted March 27, 2015, by Matt Lohry


Well, there may be a glimmer of hope, and you may be right after all! I drove by the bridge this afternoon, and the old bridge over the interstate has been demolished, but this one is still standing...and, theyve graded up to the portal to the old truss, and what looks like a loop-shaped ramp from the trail below to the bridge deck is beginning to take shape. I'm keeping a close eye on this, and my fingers crossed! I'll provide updates. This would be a major victory for historic bridge enthusiasts as well as this area!

UP - Zoo Truss
Posted December 12, 2014, by John Marvig


I spent a couple hours researching the claim. I see no record of them demolishing the bridge, no plans on any blueprints (unlike the bridge over 94); and since it's technically only a Union Pacific and Milwaukee County? Thing it shouldn't have much affect on WISDOT at all. But time will tell, fingers are crossed and hoping my sources are correct.

UP - Zoo Truss
Posted December 12, 2014, by Matt Lohry

I'd love to be optimistic right along with you, John, but frankly, I'll believe it when I see it...the new bridge is completed, and it's awfully close to the old one, much like new bridges are right before the old ones get sent to the dumpster...and, WISDOT's preservation record leaves something to be desired. I'll keep an eye on it; we pass through the Zoo Interchange from time to time, and the company I work for owns all the transmission lines in the area, and we've been replacing them to accommodate the Zoo rebuild. The lines are done and energized, and now the real roadwork begins. Time will tell with this bridge; John, I sure hope you're right!! :)

UP - Zoo Truss
Posted December 11, 2014, by John Marvig (marvigj27 [at] gmail [dot] com)

Recent report has that this bridge will be spared and left in place. Other than staying in place, I have heard nothing of a future for it. Although it's pretty awesome that they are keeping it!

Chicago & Northwestern Railway Zoo Truss
Posted May 12, 2014, by John Marvig

Any clue when they plan to demolish this bridge? I'm planning on visiting Milwaukee in June.

Chicago & Northwestern Railway Zoo Truss
Posted January 30, 2014, by Jason Smith (JDSmith77 [at] gmx [dot] net)

Say, if they want to get rid of the bridge, why doesn't WisDOT just dismantle and market the bridge to a party? THe bridge looks really fine and there are no flaws. What's the deal- scrap metal prices going up???

Chicago & Northwestern Railway Zoo Truss
Posted January 30, 2014, by Nathan Holth (form3 [at] historicbridges [dot] org)

Just because WisDOT was short-sighted enough to demolish nearly all the historic highway truss bridges in the entire state doesn't mean they should be allowed to go start demolishing railroad bridges too!

Chicago & Northwestern Railway Zoo Truss
Posted January 29, 2014, by Matt Lohry

Confirmed by an engineer with WISDOT, this bridge is being demolished and replaced this year as part of the Zoo Interchange project! This is the most prominent landmark in this area, as well as one of the very few things in this area that actually look nice. Absolutely disgraceful.

Chicago & Northwestern Railway Zoo Truss
Posted December 23, 2013, by Matt Lohry

The attack against massive railroad bridges continues--this bridge may be in danger. I noticed today while driving by that test piles for new foundations on either side of this bridge were being driven. I heard through the grapevine (verification required) the bridge is being replaced as part of the Zoo Interchange project! IS NOTHING SACRED??