S-6 Gearing

Does anyone know what gear ratio Southern Pacific S-6's were equipped with?

We will at some point need a couple of sets of gears for our RSD12. We have a spare set of roller bearing equipped S6 trucks, and am wondering if these gears are compatible.

I think, but am not entirely certain, that Alco switcherrs with 752 traction motors (S-5, S-6, T-6) used the same 74:18 gear ratio used on Alco (and GE) road power with 65 or 70 mph top speed. So check before taking my word, but the answer is probably yes.

That seems likely. I hope to be able to look through parts books next weekend.

I just don't want to make an obvious blunder thinking "Oh yah these will work" spend the time tearing the trucks down and find out they don't fit!

I'll bet the gear ratio is o.k. I think I'd want some better odds before betting that the journal boxes are the same!

The S6 we got the trucks from had been upgraded with roller bearings. (All of Southern Pacific's S6 were built with friction bearings.) Measuring the axles and boxes won't require getting friendly with sticky crater covered gears. I might get time to measure the boxes this weekend.