The E 10 express locomotive from the German Federal Railroad's first program of new locomotives was technically and, initially, visually the same as the slower E 40 freight locomotive. The exception to this was the E 10"s different gear ratio. From 1963 on, a high performance E 10.12 was built for TEE service that was given a new design for the body in addition to improvements in the running gear and propulsion system. The design for the body was influenced by aerodynamics and esthetics. The engineer's cab was lengthened and was adapted to higher speeds with a streamlined "pants crease" front and a buffer beam with additional streamlined fairing. The side vent grills were arranged as a continuous band. The regular E 10 locomotives were also given this modern design starting with road number E 10 288 and going to the last locomotive, road number E 10 510. Except for two prototypes tuned for 200 km/h / 125 mph, the maximum speed for all E 10 locomotives was limited to 150 km/h / 94 mph. Only the TEE locomotives were allowed to run at 160 km/h / 100 mph.