3751's three Coale safety valves, also known as "pop" valves, were taken off the locomotive and reset following the engine's most recent steam test. The resetting of the valves took place at a certified shop in Cerritos, Calif., which is no stranger to steam locomotive safety valves of this type. It was this same shop that reset the Union Pacific "Big Boy" No. 4014's safety valves prior to it entering excursion service back in 2019.
