Dave - that is seriously unrelated to ex-Mormonism or even ex-LDSism but I can forgive you as I am a rail freight industry consultant and have been known to foam a little at such clips.
Here is my part of the world we know your 'foamers' as 'gunzels' for some reason.
Edited 1 time(s). Last edit at 05/07/2019 08:29AM by oldpobot.
"In 1868, when the Union Pacific line neared Utah, the company contracted with Church of Jesus Christ of Latter-day Saints President, Brigham Young, to provide local contractors to lay track through the Wasatch Mountains. Brigham Young realized a railroad would create jobs, reduce the costs of goods, and improve migration for Church of Jesus Christ of Latter-day Saints converts moving to Utah. ‘Mormon’ labor crews completed part of the railroad bed from the head of Echo Canyon to the Great Salt Lake. They provided grading, tunneling, and bridge work, including digging four tunnels through Echo and Weber Canyons and creating two temporary trestles; one across the Weber River gorge and one at Promontory. Famously, the Union Pacific went bankrupt and did not honor the payments to President Young and the workers, but eventually agreed to provide rail cars and supplies to help Young construct a railroad connecting Ogden to Salt Lake City."
I gather that there are certain safety requirements which the old steam engines can't provide, e.g. braking, but I still wonder if the diesels didn't provide a little extra help.
I defer to DtA and GNPE, our resident train buffs.