dissipate current-borne electric energy as heat. Some dynamic braking vehicles describe the rheostatic braking as "plug" braking. In particular, forklift dynamic braking has been developed to take advantage of combining this type of braking with controllers specialized to quickly reverse vehicle direction. Dynamic and regenerative braking, when used on electric or diesel-electric railroad locomotives, means that the electric motors which usually are used to drive the road wheels are instead used as generators being driven by the wheels on a downslope. In regenerative braking, the electric current created is typically fed back into the power supply (i.e. overhead catenary, third rail), and can be used by other locomotives or stored for later use. In this way a locomotive will receive current while on level ground or traveling uphill, but acts as a current supply when braking, transforming the kinetic energy created from traveling downhill (or less often, converting forward momentum from travel on level ground) into electricity. In a diesel-electric, rather than being generated remotely and collected from a power source, the power supply is generated directly by the onboard prime mover (engine) and transmitted to the motors; there is presently rarely any way of storing electricity up for later use, so instead, the motors are used as generators, retarding the wheel rotation, and the generated power is routed through resistors mounted on the roof of the locomotive, where it is transformed into heat energy (much like an electric heating element) and dissipated into the atmosphere with large fans. While this has the drawback of not re-utilizing the energy created while traveling downhill, it does create a powerful and safe retarding system that is not prone to brake fade or wearing out like mechanical brakes. See also Dowty retarders Dynamic braking Retarder (railroad) References Vehicle braking technologies