I am a little dismayed after reading this thread. Geared logging engines really were not designed to be speed machines. They were, all brands of them, intended to be used on less than mainline railroads. They were invented to pull quite heavy loads on severe grades, sharp curves and steep grades. Form follows function.
Could any or all of them be run at high speeds? Certainly, for a while, but at a cost (watch the ROCK TRAIN tape about hauling dump cars with Hillcrest 10). Higher speeds means increased forces, more wear and tear, and an increase in mechanical failures, some of which no doubt were more destructive than others. Geared engines were (are) draft horses, not thoroughbreds. To expect them to be fast is rediculous.
The big problem that I often read of in the postings above was the mis-matching of locomotives with different comfortable top end speeds while double heading. This is a problem one gets into when running these geared locomotives on relatively flat, smooth, track of most present day tourist railroads (and even on old logging pikes to some extent). The train speed needs to be adjusted to the maximum speed that the slower locomotive can well handle. If one wishes to have speed, get either a rod engine or diesel.
I have spent a day or two (hostled Loggerhogger's favorite 80-3 Shay, a really good and beautiful locomotive, for four summers) on the Cass Scenic Railroad, which operates geared engines over the curves and grades for which they were intended. Uphill speeds are in the 5-6 MPH range, so the gear ratios of the various locomotives (with differing theoretical top end speeds) is not a severe problem. At Cass the locomotives are operated every day hauling loads that pretty much tax the locomotives to their max on the ruling grades. The folks at Lima, and Heisler and even Climax (eventually) would no doubt smile if they could look down to see their old products still battling gravity at Cass.
