Looking NE from the deck of the W. Cermak Rd. Bridge, you see the S. Canal St. fixed trunnion bascule (foreground) and the vertical towers of the vertical lift railroad bridge (background).
Looking SW from the deck of the S. Canal St. Bridge you see the W. Cermak Rd. Bridge.
W. Cermak Rd. - Scherzer Rolling Lift Bridge
The mechanism and machinery used to operate the fixed trunnion bascule bridges in Chicago are all below the roadway. The rolling lift bridge has its operating equipment above the roadway.
Western entry to W. Cermak Rd. Bridge - Equipment room spans roadway, counterweights at truss ends above roadway.
This bascule bridge operates by rolling back on the river bank rather than rotating about a fixed pivot point.

The rocker of the W. Cermak Rd. bridge - end view shows "track" detail; side view shows relative size.
Video of W. Cermak Rd. Bridge in Action
This video was taken near the "track" shown in the photo above. As the bridge is raised, the leaf rolls toward the camera. In the last portion of the video, the superstructure of the bridge comes into view. The audio portion consists primarily of the warning bells signaling a bridge lift.
For additional information on the Cermak bridge see Historicbridges.org.
The Amtrak bridge east of Canal St. is a vertical lift bridge built in 1915. It operates similar to an elevator, with the center span raised as the counterweights move down the vertical towers.

Looking at the Amtrak vertical lift bridge from the S. Canal St. bridge deck.
Video of the Vertical Lift Bridge in Action
This video was taken from the deck of the S. Canal St. bridge. The initial warning siren heard on the audio portion is coming from the moving bridge. All other audio (and vibration in the video) is due to the traffic crossing the S. Canal St. bridge, not from the raising railroad bridge, which is surprisingly quiet in action.
For additional information on the Amtrak vertical lift bridge see Historicbridges.org

Looking south along the S. Canal St. bridge deck.







