In common with the Krauss engines the ML 2/2 had the
axle arrangement B, semi-automatic gravity firing that enabled one-man operation, and
gangways with railings, front and rear, that allowed safe transit to the coaches. The
valve gear was, however, a completely different affair. These locomotives had two external
cylinders each with opposing
pistons that were positioned between the two axles. The axles were linked via
coupling rod on the inside.
In 1906 Maffei delivered the first three locomotives (railway numbers 4001–4003). In spite of the unusual, and for a two-cylinder locomotive, extremely complicated gear system, the engines proved themselves, and Maffei supplied another 21 examples up to 1908 (Nos. 4004–4024). The positive experience with these locomotives also led to the construction of the
Class MCCi steam
railbus, whose driven
bogie and
boiler were very similar to those of the ML 2/2.
Three locomotives were sold to the United Fireclay Factories (Vereinigten Schamottefabriken) in
Marktredwitz in 1922. The remaining machines were all including in the renumbering plan of the
Deutsche Reichsbahn-Gesellschaft in 1923 as 98 361-384. However, they were retired by 1924. The reason was the complicated and maintenance-intensive driving gear.