No. St. Louis, MO to Tulsa, OK. After 1947, St. Louis, MO to Oklahoma City, OK. Kansas City, MO to Thayer, MO.
Of all the places on the Memphis route, why did they change the 4-8-4s Mountain class locomotives out at Thayer, MO?
1. Thayer, MO was the last division point on the Willow Springs Subdivision before the Mississippi River Bridge, over which the 4300s, 4400s and 4500s were not permitted. 2. South of Thayer, the Frisco entered the Mississippi River bottomland "deltaā€¯ with its water level grades. The 4200s were quite adequate to handle on the Memphis Subdivision trains from Thayer, MO into Yale Yard at Memphis, TN.
The approaches to the Mississippi River Bridge were the ruling grades on the Memphis Subdivision. http://www.frisco.org/shipit/index.php?attachments/condensed_profile_1955_150_dpi-jpg.9579/