Rockton Rail Bridge

Pratt Pony Truss Bridge over Rock River
Rockton, Winnebago County, Illinois

Click the Photo Above to See All Photos of This Bridge!
Name Rockton Rail Bridge
Built By Chicago, Milwaukee & St. Paul Railway
Contractor American Bridge Company of New York
Currently Owned By Dakota, Minnesota & Eastern Railroad
Length 680 Feet Total, 120 Foot Main Spans
Width 1 Track
Height Above Ground 15 Feet (Estimated)
Superstructure Type Pratt Pony Truss and Deck Girder
Substructure Type Concrete
Date Built 1906
Traffic Count 4 Trains/Day (Estimated)
Current Status In Use
MILW Bridge Number E-546
Significance Moderate Significance
Documentation Date June 2014
In 1880, the Central Illinois and Wisconsin Railway built a 15 mile line from Rockton, Illinois to Rockford, Illinois.

The line split away from a Chicago, Milwaukee & St. Paul Mainline at Rockton, and met up with the Illinois Central Line across the state at Rockford.

Early information for the line is extremely unknown, although it is known the line came into the CM&StP in 1900.

By 1912, the CM&StP (Milwaukee Road) added the title "Pacific" to its name, because of the growing empire towards the Pacific Ocean.

The railroad would never recover the debts of its significant pacific expansion, but would instead falter in its competitions shadow until 1985, when it was finally purchased by Soo Line after a massive liquidation.

When Soo Line eventually became part of the Canadian Pacific, Canadian Pacific found itself unable to turn a profit on many former Milwaukee Road Lines, one of which was this one.

The line would become part of I&M Rail Link, later Iowa, Chicago & Eastern. IC&E became part of Dakota, Minnesota & Eastern (which in contrast, operated former Chicago & Northwestern Lines in Minnesota).

The Dakota, Minnesota & Eastern was purchased by Canadian Pacific in 2008, who currently operates this line as the Rockford Subdivision.

Located in the town of Rockton, this bridge features several pony truss spans to cross the Rock River.
Built in 1906, the bridge consists of four large 6-panel pin connected Pratt Pony Trusses. In addition, the bridge is approached by four deck girders on the north end and a single deck girder on the south end. The entire structure rests on concrete substructures.
The trusses of the bridge are of standard design. These types of trusses can be seen all around the Milwaukee Road system. However, these trusses are slightly larger than expected, possibly due to the later build date.
It is also possible that the trusses were actually fabricated earlier than 1906, possibly as far back as 1901 or 1902. However, there is no clear evidence to indicate this.
Overall, the bridge appears to be in good condition. This is the largest remaining such series of pin connected Pratt Pony Trusses on the Milwaukee Road system.

The author has ranked this bridge as being moderately significant, due to the truss design.
The photo above is an overview.

Rock River Railroad Bridges
Upstream MILW Rock River Bridge
Downstream Rockford Rail Bridge


Source Type


Build Date Date stamp
Railroad Line History Source ICC Valuation Information, Compiled by Richard S. Steele

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