Saxon XV HTV

Since the Saxon state railways in the Ore Mountains (Erzgebirge) had steep lines, the increased weight of the trains in the years before the First World War meant that a powerful tank locomotive had to be developed as helper or banker for freight trains. The result was the XV HTV with an unusual and complex design of the chassis, which was only built twice.

Since people in Saxony were not convinced of the suitability for everyday use of the Gölsdorff design with six coupled axles, a different path was taken in the development. Two three-axle bogies were used, but they were not mounted on bogies, but fixed in the frame. Each inner axle had lateral play of 28 mm, while the outer axles were designed as Klien-Lindner hollow axles and could be radially deflected by up to 37 mm. The latter were mounted in outside frames, which gave the locomotive an unusual appearance.

A cylinder block was located in the center of the locomotive on each side, in which a high-pressure cylinder drove the rear axles and a low-pressure cylinder drove the front axles. This resulted in a short distance between the cylinders, but a long way for the steam to travel from the boiler to the cylinder blocks and back to the blastpipe. This construction proved to be very successful in terms of wear and running characteristics in curves, but required a great deal of maintenance. In addition, the frequent slipping of the wheels resulted in different levels of wear on the tires of the two engines. As a result, the synchronization of the high and low pressure cylinders was quickly lost, so that frequent readjustment of the valve gear was necessary.

Despite this, the two locomotives did their job reliably, with the smooth running being particularly noticeable and with a top speed of 70 km/h they were relatively fast for freight trains. They were taken over by the Reichsbahn and given the numbers 79 001 and 79 002. However, their service life ended in 1932, since such maintenance-intensive locomotives could not be used economically in this small number.