Posted by:
3X
(
)
Date: May 04, 2019 01:08PM
The "spare tire" is currently present because the steam loco is undergoing trials and might be expected to have a breakdown.
The long-term situation is more interesting: the Big Boy is not equipped with PTC, and may always require a modern diesel loco (PTC-equipped) present in the train. Or it may not:
"Meanwhile, a notice published in the federal register Thursday shows that UP has asked the Federal Railroad Administration for waivers on Positive Train Control compliance for steam locomotives Nos. 844, 4014, and Challenger 4-6-6-4 No. 3985, which is stored out of service in Cheyenne."
http://trn.trains.com/news/news-wire/2018/12/13-big-boy-4014-gets-drivers-up-asks-for-ptc-waivers-for-three-steam-locomotivesPTC: Positive Train Control
https://www.up.com/media/media_kit/ptc/about-ptc/