Thanks Charles,
That is the nice kind of data we all like to see in a good discussion. Based on these figures and the 1930 knowledge of the engine, the Shay #12 could handle 4 more cars than the K-37 on the climb from Chama MP: 344.12 to Cumbres MP: 330.60= 14.06 miles but it would take 84 minutes of running with a service stop at Lobato, and water stop at Cresco. Total would be 100 minutes and Las Pinos would be the best transfer point so as to handle a larger train westbound than a K-36 can handle on that grade back up to Cumbres.
Also, everyone thinks of Cumbres grade as being 4% when the average grade in 153.05' per mile, which is under 3% grade on the average run. The Shay can run faster than 10 mph when not on the maximum 4% grade. The true time could be much less than 100 minutes.
If anyone can't see a Shay doing this job every day, they have never been to CASS SCENIC RR, where it is done daily and on a 11% grade for a part of it.