Being from Australia this topic interested me, for a couple of reasons.
1: Walthers TT: I got caught with one of the 90 footers as well. It looks the part, & almost identical to out NSW 90ft tables. Problems with it included, flimsy weak plastic, jerky rotation, & very ambiquous instructions on how to power the thing.
I checked out the new powered 130ft table, totally unprototypical for our conditions, but for the price of $400.00, I chose a locally produced one that measured in at a scale 125ft. Again not prototypical but makde of pressed metal, brass & some urethane. The reason why the table was built oversize was for those who model U.S railroads, but also for those who have various versions of our garrats. While they were 100" wheel base they were ove 106 length over buffers, & in the model form some came in at a scale 115 wheel base, so the 125 was a compromise. it comes with a belt ddrive & pin indexing, the problem with this is that it stops at each road, but at the price & the utter strength of the table it is the best option, although expensive.
I also checked out the people who advertise in MR turntables made to order. With exchange rate too expensive, beside they never answered 3 emails of mine.
2: We had a common use of the turntables in depots with roundhouses beside just for entering, storage & departing engines. Often engines in repairs were required to be moved, or the engine & tender seperated to different roads or, a dead engine to be turned & put back into the same or another road for additional work.
This required the positioning of in steam engines on the different roads across the table. An engine would thus pull the dead one on to the bridge, where the engine was chocked & set, the engine in steam would move off the bridge, & stable. The required turning would take place, with an engine positioned opposite the locations where it was required to be put, then the engine would be pushed & positioned in its new position.
This also occured in some depots where wagone repair facilites were available, & the above events took place with wagon moves.
Colin Hussey