Since the S 10 was found after a short time to consume a lot of water and coal, the development of a more economical locomotive with a compound engine was started. Although the designation suggests otherwise, the S 101 was not related to the S 10 in terms of design. The class only included express locomotives with a 4-6-0 wheel arrangement, in reality the S 101 was a completely new design and was not based on the P 8 like its predecessor.