Although the express locomotives with 4-4-0 wheel arrangement known from America had become increasingly widespread in Central Europe, the Württemberg Railways wanted to return to cheaper locomotives with a 2-4-0 wheel arrangement at an early stage. In addition to some rebuilds from 4-4-0 locomotives, the class A was also produced, which was manufactured from 1878.
An important point in the cost savings was the chassis, the three axles of which were all fixed in the frame. A relatively small driving wheel diameter of just 1,650 mm made it possible to achieve a wheelbase of just four metres. It was thus possible to achieve good curve running characteristics even without a flexibly mounted leading axle. The locomotives were recognizable by a very large steam dome and a firebox that was higher than the boiler barrel. In the first batch of ten locomotives from 1878, the boiler pressure was ten bars, in the 15 built later this was raised to twelve bars. The latter also received cylinders with a slightly increased diameter.
With a top speed of 80 km/h, the locomotives were able to assert themselves in express train service for a long time, but the small wheels and short wheelbase became a disadvantage at the latest when new express locomotives were put into service. They were later reclassified as class Aa, but around the turn of the century, after being fitted with a new boiler with a pressure of 14 bars, they were given the designation A again. They were last used in regular passenger service, but the last two locomotives were even able to hold their own until 1925. They were taken over by the Reichsbahn as numbers 34 8101 and 34 8102, but were retired in the same year.
