Auxiliary Circuit Cubicle HB1 & HB2 for Electric Loco

Auxiliary Circuit Cable 1 (HB1) and Auxiliary Circuit Cubicle 2 (HB2) for Three Phase Locomotive are panels of contactors, switches, circuit breakers, etc. It controls the input to several auxiliary assemblies of the locomotive like machine room blower, compressors, crew fan cab heater, etc.