Description
In the 1960s, the testing institute Halle needed another high-speed steam locomotive to test new passenger cars. The new machine 18 201 was developed from the high-speed tender locomotives 61 002 and parts of the high-pressure test locomotive H 25 024. A modified new boiler of the 22 series with an extended smoke chamber and Giesl ejector served as steam generator. To accurately maintain the speed when driving fast, the machine is fitted with a back-pressure brake. Fast travel meant up to 175 km/h, because for this top speed the 18 201 was initially permitted, later 180 km/h, but only forward.
