B&SR no. 8 arrives at Sheepscot

[John McNamara]

Now we know that the turntable will handle 38 tons.....once.

[Kevin Kierstead]

what is the rated tonnage for the turntable?

[Rick Rowlands]

38 tons?

[Jeff Schumaker]

Didn't  WW&F #6 get turned on the original turntable at Wiscasset?

Jeff S.

[Graham Buxton]

Harold Downey drew up the plans used to construct the current WW&F turntable. Here are his comments on weight ...

Overall, this turntable bridge is a very robust structure.  The stresses in all the main elements are very low.  The primary limiting factor was deflection, which was governed by the longitudinal beams.  The truss elements function to keep the loads on the perimeter rail and wheels near zero once the locomotive is centered.  In fact if you look at some of the historical photos, there is only a partial perimeter rail. 
Finally, the bridge would still function without the truss, but it would be harder to turn.

For the stress analysis, I used the biggest WW&F locomotive as the design load --the 26 ton #6. 

It was quite fun to look at the historical photos and analyze the changes from the Portland Co. drawing.  Folks have noticed the tie rod between the queen posts so far.  There are quite a few other differences, some of them subtle.  Our turntable will be very much like the historical photos.

That quote was posted early in  the "Official Turntable Work thread" started several years ago. Here is a link to the beginning of that thread:
http://forum.wwfry.org/index.php/topic,2628.0.html

[Philip Marshall]

I had assumed the 26-ton weight for No. 6 was the engine only, not counting the tender. Is this incorrect?

[Benjamin Richards]

No, you are correct; that figure is for the engine only. A fully-loaded tender would add roughly half as much again.