PRR's South Branch Bridge Interlocking Tower

When researching the Canal Street RR Bridge, I learned that control of the bridge was transferred from the machinery building on top of the span to a "nearby interlocking tower." The building on the right in these photos is that interlocking tower. It controls the bridge and the signals regulating the crossing of the bridge. There was a larger tower southeast of this one that controlled the 21st Crossing.

Posted by Bill Molony on Facebook
Bill posted again
Pennsylvania Railroad Baldwin DR-6-4-2000 "Sharknose" #5786 departing from Chicago with PRR train #52, the Fort Pitt on July 4, 1949.
David Nelson April 27, 1947 - April 28, 1968.
Dennis DeBruler One of the better views I have seen of the bridge control tower.

Bob Lalich commented on a post
The cabin seen right of the tracks controlled the interlocking depicted in this drawing. I believe the bridge itself was controlled by an operator in the structure on top of the span.

Dennis DeBruler commented on Bob's comment
When built, it was controlled from a room in the shadows under the machinery house. But when I researched the bridge, I read that control was transferred to "a nearby interlocking tower." Unfortunately, I didn't note the source of that statement. I searched some references, but I was unable to find that statement again.

Thanks for confirming that the little tower was an interlocking tower.

Bill Molony posted on Facebook

Willam A. Shaffer posted
Amtrak E8A #201 (ex-B&O #1443) - Chicago, IL (Circa 1973)
(Photo by Mike Parafink - Collection of William A. Shaffer)
AMTK #201 is shown crossing the 21st Street Bridge in Chicago.
[Note that we can see part of the bridge tender's shack. Also note the top signal head can display only the "red eye" aspect.]
Willam A. Shaffer posted

B&O E8A Locomotive .(June, 1973)

21st Street - Chicago, IL

(Photo by Mike Parafink - Collection of William A. Shaffer)

Mark Jones: William A. Shaffer, Ex-B&O E-unit ( probably 1457?!) and look at the South Branch Bridge in Penn Central script w/ “W-19”— do you remember what that meant? !? It was for the trainmen and told them “track 19, West side platform unloading”…. Still remember that after all these years!
William A. Shaffer: Yes, I still remember the designations and what they meant! Seems like just yesterday!

Gordon Leonard posted
It's still Feb. 1976. We're still at The Bridge. Check out the damage at the lower right front. It hit something....!
Bjarne Henderson They ran fast and were a pleasure to work on from a service attendant's perspective. They had access doors near the food service area so you didn't need to schlep all your stuff from one end of the car or the other as you still have to do with Amfleet. Clearly, whoever designed the Turbocafe considered the needs of employees as well as the passengers. Too bad that they wore out too quickly compared to their peers.
[Note the signal heads are missing many positions because only slow speeds are indicated for crossing the bridge.]

Steven J. Brown posted
Amtrak International departs Chicago for Toronto at 21st Street - September 12, 1988. The International used to alternate VIA/Amtrak equipment every other day. VIA Rail F40PH-2 6407 was built in 1986).
Dennis DeBruler It shows the one-story bridge tower by the bridge and the interlocking tower a little to the east.

John Dziobko's 1962 photo shows the "red eye" head illuminated. A 1955 photo of a C&WI commuter train shows the "stop" head before it was converted to a "red eye."

Mike Breski posted GM&O 101 crossing the bridge.
Bob Poortinga One of the few photos I've seen that shows the PRR South Branch Bridge interlocking shanty. The block operator also operated the bridge. If you look closely, you can see the PL signal that protected the bridge. This was *not* part of 21st St. Interlocking. If you look even more closely, you can see part of the backside of the home signal for 21st St just above the engineers location.
Dennis DeBruler While trying to find the link for the above photo, I found a similar view.
http://rrpicturearchives.net/showPicture.aspx?id=1880219
Dennis DeBruler Sam's upload: http://cachman.rrpicturearchives.net/showPicture.aspx...
[Additional comments discuss Pennsy's 22nd Street Tower.]