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Government (Arsenal) Bridge

Baltimore Through Truss Swing Bridge across Mississippi River
Rock Island, Rock Island County, Illinois
To
Davenport, Scott County, Iowa

Click the Photo Above to See All Photos of This Bridge!

Name Government (Arsenal) Bridge
Built By Chicago, Rock Island & Pacific Railway
Contractor Ralph Modjeski, U.S. Army and Phoenix Bridge Company
Currently Owned By Iowa Interstate Railroad Railroad
Length 1,854 Feet (365' Swing Span)
Width 2 Tracks, 2 Vehicle Lanes
Height Above Ground 15 Feet to Normal Water Level
Type Baltimore Through Truss with Pratt Through Truss and Steel Beam (Road)
Date Built Opened 1896
Traffic Count 3 Trains/Week (Estimated)
Current Status In Use

In 1855, the Mississippi & Missouri Railroad Company began building an extesive network of railroads in Iowa.

The largest line connected from Illinois, on the Rock Island side of the Missippi, crossed the Mississippi and began heading west.

This crossing of the Mississippi is one of the most famous, and is the first known railroad crossing of the river.

The line was completed to Wilton (25 miles from Davenport) by September 19th, 1855.

At Wilton, a line would eventually be completed heading south to Muscatine (13 miles), at which point the railroad completed a new line from Muscatine to Washington (30 miles south of Iowa City)

The future mainline was continued, making it to the capitol of Iowa City by December 31st 1855.

Between 1860 and 1865, the line was eventually extended to Kellogg, about 45 miles east of the new capitol, Des Moines, which became the capitol in 1858.

The railroad became part of the Chicago, Rock Island & Pacific (Rock Island) on October 20th 1865.

In 1867, the line was extended to Des Moines, where it met up with what was formerly known as the Des Moines Valley Railroad.

From here, it was extended to Council Bluffs Iowa in 1869, a distance of 141 miles.

Beginning in 1896, the Rock Island took on a big challange by double tracking up until West Liberty, 20 miles east of Iowa City. Most of the line was reconstructed between Council Bluffs and Chicago between 1895 and 1902.

After years of doing well, the Rock Island began to fall apart by the 1960's. The Union Pacific attempted negotiations to merge with the Rock Island, which fell through.

In 1981, the ICC ruled that the Rock Island would be liquified. The Chicago North Western Railroad purchased much of the Iowa and Illinois lines.

The one line they didn't acquire was the mainline from Chicago to Los Angeles. This is due to the fact they had a mainline just north of that line.

The mainline became part of the Iowa Interstate in 1987, which has become an extremely successful railroad today.

The Union Pacific Railroad acquired the C&NW in 1995, meaning it would have been interesting should have the UP merged with the Rock Island.

Today, the Iowa Interstate is heavily used, with about 4 trains per day at any given piece of tracks. The IAIS is a prime example of hard work, and luck.
01/16/17


Perhaps the most famous railroad bridge across the Mississippi River is the Government Bridge, locally known as the Arsenal Bridge.
The bridge carries dual lanes of traffic and two tracks of Iowa Interstate on its 8 spans across the Mississippi.
The bridge was completed in 1896 and designed by chief engineer Ralph Modjeski. The US Army was in charge.
Also called the Rock Island Bridge, it connects to Rock Island Arsenal, a Government Instalment.
The main span is 365 Feet Long, and crosses part of Lock and Dam #15.

This was also the site of the first railroad bridge across the Mississippi, built 1856. This bridge was replaced in 1872 with another wooden bridge. This bridge served is usefulness and was replaced by this structure in 1895.
The first bridge was destroyed in 1856 and a young Abraham Lincoln defended the railroad. This bridge was located about half a mile upstream.

All the spans on this bridge are pin connected, with the exception of the vehicle approach on the west end.
In addition they all contain X frame portal Bracing. The difference is spans 2 through 7 are Baltimore Through Trusses with two decks, and 1 and 8 are railroad only pratt through trusses.
As taken from the HAER documentation:

"The piers and abutments (see HAER Photo Nos, IL-20P-1, IL-20P-2, IL-20P-7, IL-20P-12, IL-20P-14) are constructed of limestone with sandstone facing. Abutments support each end of spans A and H; piers support the ends of spans 2 through 7 in the river, as well as the midpoint of span 7, the swing span. Except for the swing span pier, which is larger than the others, the various piers are relatively equal in size.

Spans 1 and 8 (see HAER Photo Nos. IL-20P-4, IL-20P-6, and IL-20P-20) serve as approaches to the bridge. They are substantially smaller and shorter than the other spans, rising from a level equal to the railroad bed. All other spans rise from a level equal to the lower vehicular road bed. The vehicular roadway has no approach spans, traversing only spans 2 through 7.

All trusses are tied at their top (see HAER Photo Nos. IL-20P-1, I1-20P-5, IL-20P-6, IL-20P-8, IL-20P-9, IL-20P-10, IL-20P-12, IL-20P-21, IL-20P-23, and IL-20P-24) with riveted steel members at each panel with diagonal cross members in each bay. A smilar set of steel members (see HAER Photo Nos. IL-20P-11 and IL-20P-13) is used to tie the two sides together under the railroad deck and under the vehicular road bed. The control room (see HAER Photo Nos. IL-20P-1, IL-20P-5, IL-20P-8, IL-20P-9, IL-20P-18, IL-20P-19, and IL-20P-25), in the upper, center of the swing span, is reached from the vehicular roadway level by two, straight-run, open, steel stairs on the east side of the bridge, rising to the railroad track level with a shared steel deck landing, then continuing upward to the control room level. The room is surrounded by a narrow, steel walkway with a metal deck and pipe railing painted black. From the south walkway a steel cage ladder rises to a steel landing above the roof, which gives access to the steel ladder rising to the turntable for the upper swing span.

The control room is square in plan with a hipped roof covered with standing-seam copper roofing painted black. Roof, wall, and floor systems are all sawn wood members. There is a set of semi-circular metal gutters on all four sides of the roof. Decorative pressed-metal shingling painted black covers all four walls. The east elevation (see HAER Photo No. IL-20P-9) has a single doorway on its south end containing an original wood door with four lights over three panels and a modern raw aluminum storm door. To its north is a single window opening. Two single window openings are located on each of the south and west elevations. An octagonal bay window (see HAER Photo No. IL-20P-25) is centered in the north elevation with a single window opening in each of its three faces. All eight window openings contain one-over-one, double-hung, wood sash with plain interior and exterior, painted, wood casings.

The one-room interior (see HAER Photo Nos. IL-20P-18 and IL-20P-19) has wood floor covered with linoleum tile, overlaid with loose strips of carpeting. The walls are covered with horizontal, beaded, tongue-andgroove, board siding. In the northeast corner is a pair of cabinets made of vertical, beaded, tongue-and-groove boards. In the center of the west wall is a wood shelf, dating from the original construction. The walls, cabinets, and shelf are all painted cream. The cabinets each have a set of three butterfly hinges and single latches. The shelf is supported by two decorative, cast iron brackets. The ceiling is acoustical tile attached to the original, tongue-and-groove, board ceiling. Near the south wall an inclined wood ladder leads upward to the ceiling hatch giving access to an unfinished attic used for storage. Lighting is by flourescent and incandescent fixtures. There is an air-conditioning unit in the south window of the west wall. A modem electric heating unit supplies the necessary heat. An older electric heating unit survives along the west wall.

Along the south wall of the control room is an original, 550-volt, General Electric, motor-generator set, which converts alternating current to direct current in order to run a 50-horsepower motor, which, in turn, powers the drive train machinery for the swing span. A series of bull and bevel gears for the power train occupies the center of the room, surrounded by a polished brass guard rail (see HAER Photo Nos. IL-20P-18 and IL-20P-19). In addition to a control board on the north wall, the room also houses an alternating-current, motorized, direct-drive, air-compressor unit, which, at an undetermined date, replaced an original belt-driven unit. The air-compressor activates the pneumatic jacks underneath the swing span and the pneumatic rail locks on the railroad bed. The pneumatic system operates under 100 to 120 pounds per square inch of pressure, which is maintained by two original, riveted, steel, air-storage tanks located in the attic above the control room."

Complete coverage of it can be seen here:
HAER Documentation of Government Bridge

In addition, the photos can be seen below as well as on This Site

The photo above is looking at the Swing Span.

Mississippi River Railroad Bridges

Upstream Clinton Rail Bridge
Downstream Crescent Bridge


These Pictures Start at varying points in the Series

From Iowa Side

Detail Pictures

Historic American Engineering Record Pictures



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