Re: Speed record - What the Timetables show

Rick,
Where did the 1.1 rule come from? I have heard it mentioned before, but is it simply a safe operating rule of thumb, or is it an actual upper limit for older power? Using it, the 46" drivers on a T-12 would produce 50mph, pretty close to the 56 mph average speed reported in El Coke's post.
I suspect that the T-12's had pretty light running gear, with less reciprocating mass to deal with, plus the 4 wheel lead truck would also increase stability. Sixty mph is about 80% of 540 rpm, the generally accpeted upper limit for modern steam power, so it might well have been possible.
The Sandy River Forney's, also equipped with a four wheel bogie truck, were reported to have run in the 60 mph range, so why not the T-12? Track condition would probably have been the limiting factor.