Heusinger's railway passenger car as a mobile hospital from 1876. Illustrated with 10 black and white images. Edmund Heusinger von Waldegg (1817 - 1886) was a mechanical engineer and railway engineer. In 1849, he invented a novel control system for steam locomotives, known as the Heusinger control. It became the most widely used system in the world. He also invented the D-train car, the "Heusinger car," which, unlike the compartment cars predominantly used in Europe at the time, featured an interior side corridor. This made the previously external footboard, which was only used by train staff under considerable danger, unnecessary. The Hessian Ludwig Railway was the first to use this new type of car, and the Prussian State Railway introduced it into regular service in 1891. Among his other inventions was a field railway system for the army.