In order to get a more powerful successor for the large number of existing branch line tank locomotives, the class 423.0 was developed by the First Bohemian-Moravian Machine Works (PCM) and also manufactured by other companies. In order to achieve the greatest possible power, the choice fell on the 2-8-2T wheel arrangement. Later they also formed the basis for the 433.0 series.

A lot of attention was paid to the running gear in order to achieve sufficient running characteristics on branch lines despite the six axles. While the two carrying axles were designed as Adams axles, the third coupled axle, which served as the driving axle, was equipped with weakened wheel flanges and the first coupled axle could be shifted by 21 mm to each side. A water purifier was installed to take account of the often polluted boiler feed water on branch lines. This was cylindrical and, together with the steam dome and the sandbox, lay under a panel on the boiler barrel. 

A total of 231 units were manufactured until 1946. With an indicated output of more than 750 hp, the engines were also called “Velký Býcek” or “Big Bull”. Some engines in the Sudetenland came under the control of the Deutsche Reichsbahn from 1938 and were listed as the class 93¹⁵ at this time. During the Second World War they all came back to the CSD area. They were in service until the late 1970s and it was not until 1980 that the last two examples were retired. Five examples survive today, three of which are in working order.

Schematic drawing with dimensions

Die Lokomotive, June 1935

From 1933, the ČSD had tank locomotives built by Škoda and ČKD for express trains in the mountains. They received assemblies from existing locomotives. The chassis was designed in such a way that curves with a radius of 150 meters or more could be negotiated. When the Sudetenland was annexed, 15 locomotives came to the Reichsbahn and became the class 68⁰. In Czechoslovakia they were only retired between 1973 and 1981.

For suburban trains, the ČSD developed a tank locomotive with a 4-8-4 wheel arrangement, which was developed using the latest design principles. It was based on the single class 475.0 tank locomotive and the four class 476.0 tank locomotives. At the time of delivery, they were the largest tank locomotives in Europe.

The boiler had a combustion chamber, a mechanical stoker, a rocking grate and a double Kylchap blastpipe. There were also Trofimoff valves, power reverser and roller bearings. The three cylinders worked with simple expansion. Visually, the locomotives were clearly reminiscent of the German standard locomotives, especially with their Witte smoke deflectors and the steps at the front.

The first 38 locomotives were put into service as class 476.1. Due to the water reserves, they were very rear-heavy, which caused an uneven distribution of the loads on the driving axles. On the remaining 22 locomotives, the rear storage tanks were shortened by 30 cm and the side water tanks were lengthened to the front. To optimize the boiler's performance, the combustion chamber has been lengthened, thereby shortening the tubes and flues. These locomotives were designated as the class 477.0 and all earlier ones were rebuilt in the same way.

They were primarily used in the area of large cities in front of passenger trains, but also in front of freight trains if necessary. During test runs, speeds of up to 115 km/h were reached and 96 km/h were possible on flat land with an 800-tonne train. The same weight could be transported at 0.5 percent at 53 km/h and at one percent at 35 km/h.

The class 477.0 was not phased out until 1971. With the electrification of many lines and the introduction of more and more diesel locomotives, they gradually disappeared until 1981 when none were in use anymore. Three are still operational today, the 477.060 had even been in the Augsburg railway park for a few years since 2009.

For the increased demands in freight traffic after the end of the war, a total of 510 freight locomotives were made by Škoda, which had the same boiler as the 4-8-2 locomotives of the class 475.1. All the modern achievements of steam locomotive engineering were used, such as a boiler pressure of 18 bars, Kylchap blast pipe, stoker, roller bearings and more. The result was a locomotive with a low axle load that was still able to pull freight trains weighing 3,000 tonnes in flat country tests. In practice, two locomotives pulled coal trains weighing up to 4,000 tonnes and they sometimes had to assist in front of express trains in the mountains. They were also used in neighboring countries and in 1983 were the last regular steam locomotives operating in Czechoslovakia.

Since the expected number of passengers in express traffic in the 1930s was low and the existing tracks did not allow high axle loads anyway, the Hungarian State Railways developed a light streamlined tank locomotive. With one bogie in front and one behind, the four locomotives were allowed to travel 120 km/h in both directions. A speed of 152 km/h was reached during a test drive and in 1961, after the installation of a double blast pipe, even 160 km/h were reached. As with German streamlined locomotives, the panels were later cut out in the area of the wheels.