Fuel tender No. 400, late 1970s.

In the photograph above, Amtrak fuel tender No. 400 wears the original company logo. Originally built as an E9A locomotive, the unit was reconfigured in 1978 to serve as a prototype fuel tender that held 9,300 gallons. Placed between two SDP40F locomotives, it eliminated the need to refuel a train for up to 2,500 miles. Amtrak designed the prototype tender in response to new federal environmental regulations that required updates to more than 70 fueling points--an expensive, multimillion dollar project.