Underframe of a passenger train steam locomotive, Class 3.1, 1:5 scale model Passenger train steam locomotive, Class 3.1, Side view 1 (on the right)

In the last decades of the 19th century, the design of a passenger train locomotive that included a leading axle and two driven axles was widely adopted. One of these, the "Ruhr-Sieg railway type" of the Bergisch-Märkischen Railway, was in 1884 further developed into the Prussian Class P 3.1 with two cylinders and internal Allan valve gear. 617 of these models were built by 1897. It could achieve a speed of 80 km/h on a level track when pulling a 185-ton load. Its use was discontinued around 1923. This model was produced by the Witten Main Workshop in 1905.

Side view from the right