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Anyone REALLY need a turntable--or four?????? in Pa.
https://www.rypn.org/forums/viewtopic.php?f=1&t=45341		 Page 1 of 1
Author:  Alexander D. Mitchell IV [ Sat Mar 13, 2021 11:31 pm ]
Post subject:  Anyone REALLY need a turntable--or four?????? in Pa.
This is a case of being caught off guard.

This listing (newly created by me) is for a bridge across a river channel to an 880-acre island owned and maintained by the Pennsylvania Game Commission as a hunting preserve ("State Game Lands" is the technical name):

http://bridgehunter.com/pa/dauphin/bh92390/

This is such an obscure bridge that even I had only been to it once despite being both a bridge buff and living less than 40 miles away in my younger days, and never looked that hard at it. It's obscured by trees most of the year as you drive by at 60 mph.)

My associate, who sent me the photos, said, "What's with those girders?"

One look, and you can guess why I freaked out.

A closer look shows three spans appearing to be identical design to one another with a fourth of a different design, and two regular plate girders at each end of 50-foot length (all Google Earth Pro estimates).

In trying in vain to do research on this bridge (a bridge owned by the Pa. Game Commission doesn't appear in the National Bridge Inventory, for one), I found an expired Request For Proposal for new I-beams for this location. Obviously they weren't procured or installed yet.

We estimate the turntable girders to be 75 feet each.

1) does anyone, by any miracle, have any history on this bridge?
2) IF I should find this bridge is being replaced, does anyone in the Northeast still have a use for a 75-foot turntable?

Image
Author:  jrevans [ Sun Mar 14, 2021 9:08 pm ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
That's a pretty neat find Alexander! (or does everybody call you Sandy?)

This page has some detailed pictures of the bridges taken by kayakers on the river:
http://www.crownover.com/susquehanna20071022.html
Author:  nedsn3 [ Mon Mar 15, 2021 12:01 pm ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
The former Gassaway, W.V. turntable survives as a bridge "somewhere" in WV.
Author:  cjvrr [ Mon Mar 15, 2021 2:14 pm ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
Wonder if they every really had been turntables, or did the steel mill give someone a good deal on surplus turntable beams?
Author:  Dennis Storzek [ Mon Mar 15, 2021 3:46 pm ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
Either way they come without the center bearing, which would seem to be a major sticking point if returning them to railroad service is contemplated.
Author:  Randy Gustafson [ Mon Mar 15, 2021 3:56 pm ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
Wow, that's amazing. I've passed that location literally hundreds of times.

I thought it was a converted rail bridge, but it's obvious it's a limited-access road bridge, which is why it would be replaced. Can't be for weight limits. So they started with secondhand turntable girders to begin with.

https://www.pgc.pa.gov/HuntTrap/StateGa ... L__290.pdf
Author:  John T [ Tue Mar 16, 2021 9:04 am ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
I see in the photos that at least one of the spans has a builder's plate still attached. Might give a clue to where it came from.
Author:  dieselloco [ Tue Mar 16, 2021 6:00 pm ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
Turntables weren't designed to bear weight at the ends. The center bearing takes almost the total load. Hence armstrong turntables which use the cantilevered part as a lever. You can see openings in the ends where wheels may have been attached. Awesome find!
Author:  crij [ Wed Mar 17, 2021 11:48 am ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
dieselloco wrote:
Turntables weren't designed to bear weight at the ends. The center bearing takes almost the total load. Hence armstrong turntables which use the cantilevered part as a lever. You can see openings in the ends where wheels may have been attached. Awesome find!


Actually once they got longer than 75' the ends started bearing the load when rotated. This is why they had to install roller bearings in the outriggers, as the center and both ends were in supported at all times. Under 75' they were able to balance on the center bearing without the bridge flexing too much. This is also why almost no turntables above 60' were built to be spun under man power alone.

Rich C.
Author:  ArtS [ Fri Mar 19, 2021 10:50 am ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
Is the bridge at risk?
Author:  Alexander D. Mitchell IV [ Sun Mar 21, 2021 11:48 pm ]
Post subject:  Re: Anyone REALLY need a turntable--or four?????? in Pa.
I've been contacted by an engineer with the Pa. Game Commission.

They have utterly no records on the bridge's construction or history (that they've found so far), but assert that the requested beams were for another project ON the island, and that the bridge is not planned for replacement currently.
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