Injured employee was operating a diesel locomotive on the 3 West Haulage pulling 5 empty shield carriers and 1 rockdust supply car when they lost control of the trip and began sliding. Slid down the 3 West Haulage to the 8 blk. track spur on the 4 West Haulage where it derailed the locomotive and trip and hit the corner of the coal rib straining neck/back.