Shortly after the turn of the century, the Stockholm-Västerås-Bergslagens Railway built a small inspection engine with only one cylinder. The power section had two axles, of which the front one was powered. Its drivers had a diameter of only two feet or 610 mm. There were three seats behind the boiler, all of which were in reach of the controls. The carriage section had a length of 11 feet or 3.35 metres and offered space for five persons. In it were a sofa, a chair, a table and a washstand. This vehicle usually traveled at speeds of nearly 29 km/h and is said to have reached 60 km/h on good days.