Why none of the 30 Frisco 1500 Class 4-8-2 Mountains ran on the Frisco River Division between Memphis TN and St Louis MO
These were passenger engines, and I imagine none of the passenger trains on the River Division were heavy enough to require them, with the 1000-class Pacifics up to the job Also, the 1500s were needed for runs in the hilly Ozarks, not so much for the more level River Division.