ABS (CB&Q) 1911 Bridge over Missouri River in Kansas, MO

(Bridge Hunter; Historic Bridges; HAER; 3D Satellite)

ABS stands for Armour, Swift, Burlington.

This was a dual deck bridge that carried tracks on the lower deck and, initially, a trolley on the upper deck with road outriggers from the upper deck. Later, the trolley was replaced by two more (skinny) lanes of traffic. Except for the navigation span, the tracks were in a through truss and the trolley was on a deck truss. For the navigation span, the trolley was in a through truss and the tracks were on a deck that hung from that truss via steel columns called hangers.

Google Book, p772

Old Postcard from Bridge Hunter

Randy Volskay posted
 NS transfer run crosses the Armour-Swift-Burlington draw bridge, in Kansas City, Mo. This is a pretty unique span. The truss sits above what used to be the highway deck, and the vertical plate columns would lift the track girders to the required height. The highway was moved, about 25 years ago, but the railroad portion, obviously, still moves along.

Postcard Digitally Zoomed

On top of the navigation channel truss, above each hanger, was a sheave (pulley). On both sides of each portal was a drum with grooves. On each side of the adjacent road deck was a line of sheaves. These sheaves allowed steel cables to be strung from the top of each hanger to its own counterweight. (Actually, the end of the suspended deck must have had a couple of cables going directly to the suspended deck without a hanger because I don't see a hanger and I see two smaller counterweights.

The portal photo below shows the road configuration after the trolley tracks had been removed.

photo from MO,48-KANCI,16--9 from mo0450

Digitally Zoomed from the .tiff copy

This closeup shows how the cables passed over the end of the bridge. The shaft on the right goes into the machinery house. There are gaps between the cables compared to the number of groves in the drum because each cable is wrapped more than one revolution around the drum and then connected to a counterweight. This provides enough friction so that this powered drum can raise and lower the track deck. (The counterweights should be adjusted so that it takes about the same amount of power to lower the deck as it does to raise it. I know when they paint a drawbridge in Chicago they have to adjust the counterweights to compensate for the change of the bridge weight caused by the paint job.) It appears that two steel cables are used for each hanger/counterweight connection.

Initially, the deck could be raised in 50 seconds, but due to the age and condition of the machinery, it now [1984] takes about three minutes. The synchronization of the two sets of machinery at either end is handled by a counterweighted rope drive connecting opposite motor shafts. The motors are connected electrically and both operate simultaneously. In case either should be out of service, the lifting deck can be operated by a single motor from either end, the machinery at the opposite end being operated through the rope drive. Limit switches cut off the current to the motors and apply the brakes near each limit of movement. [HAER, p10]

modot_293A_004, July 14, 1951
Disasters, Floods, 1951: Three unidentified men examining flood damage on the washed out railroad level of the ASB Bridge over the Missouri River, Clay County

Randy Volskay posted
Coming home, today, and the old ASB draw bridge, across the Missouri River, in Kansas City, was raised (all the other spans were open, as well). This isn't a frequent event, and I've never been fortunate enough to have seen it.

James Clary posted
One from Kansas City
Blair Denny When I worked for the KCS as a conductor and engineer, we delivered empty coal trains to BNSF Murray Yard in North Kansas City from the KCS's Knoche Yard in Kansas City over this structure. (More often we were routed over the Kansas City Terminal and BNSF along the Bluff Track to the Hannibal Bridge.) This photo of the ASB Bridge is looking north over the Missouri River. The large span over the river's channel lifts vertically.
(Facebooked)

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