Royal Prussian Union Railway class S3

From Wikipedia, the free encyclopedia

S3 was a class of steam locomotives manufactured from 1893 onwards for Royal Prussian Union Railway, and later, for other German state railways.

[edit] Design

Its "S" standing for Schnellzuglokomotiv, or express locomotive, S3 was of a large and powerful type. It was the first class of locomotives to use superheating, a process in which the steam leaving the boiler is re-heated, resulting in better efficiency.

The locomotive had one high-pressure and one low-pressure cylinder, coupled to four driving wheels in 4-4-0 configuration.

More than a thousand S3 class locomotives were built over the years. In addition, several hundred units with smaller driving wheels were manufactured - dubbed the P4 class.