Controls Today’s railroad cars incorporate many safety features. Ladders have rungs that prevent feet from sliding off. There are grab bars at climbing transition points and slip-resistant walkways and handrails. Thermally insulated tank cars prevent heat buildup and explosions from fires in adjacent cars. Cars carrying hazardous materials have interlocking couplings. Locomotives have dead-man controls to prevent runaway trains should an engineer become incapacitated. Cars containing hazardous materials have placards indicating contents and type of hazard. Automatic sensors placed strategically along main lines detect overheated bearings.