Einheitsdampflokomotive - Design Principles of The Einheitslokomotiven

Design Principles of The Einheitslokomotiven

In many cases, rivetted, sheet steel, locomotive frames were used on the older steam locomotives as a support for the running gear and engine. For reasons of stability, this frame had to be of a certain height. To meet the increasing demands in performance on the newer engines, a larger boiler was required, for which there was not enough room for the high-sided sheet metal frame. As a result the new Einheitslokomotiven had a lower and more solid bar frame. In addition, the higher performance demanded, required a larger boiler heating area; this was achieved by extending the boiler barrel.

The use of individual components or systems such as, for example, the boiler, the carrying bogies, etc., for as many classes as possible, enabled considerable savings to be achieved in construction, in repair and in the stocks of spares parts needed.

So, just externally, German Einheitsdampflokomotiven can be recognised from their bar frame, their large, long boilers and corresponding short chimneys, the standardised appearance of systems like the bogies, driver's cabs and associated tenders, as well as the typical, large Wagner smoke deflectors and, later, the smaller and more elegant Witte deflectors in front of the smokestacks.

Numerous improvements and optimisations were carried out on the new designs. For example, in the boiler, the heating areas and tube cross-sections were more carefully matched to one another to make best use of heat generation. At the same time the flow of smoke gases was optimised by the superheater tube system to minimise suction draught. The low position of the blast pipe in the larger smokebox at the front of the boiler is the least visible feature of the Einheitslokomotiven.