When the Bosnian-Herzegovinian State Railways put the route over the Komar Pass into operation as the next 2 ft 6 in rack railway after the Narenta railway in 1894, more powerful rack locomotives based on the Abt system were needed. The basis for the development was the class IIIb4, which had three coupled axles and a single-axle Klose supporting tender and was already in use on the Narenta railway. Adding a second axle under the supporting tender allowed not only to increase the supplies, but also to carry the load of a heavier boiler.

Technically, the locomotives shared many similarities with their predecessors. Due to the small gauge, an outer frame was still used, and the cylinders of the rack drive were still on the inside. In adhesion mode, still the the third coupled axle was powered. There were minor differences between the individual production series, for example the grate surface was initially reduced from 1.66 to 1.58 square meters. Also, some engines were oil-fired to improve visibility in tunnels. Compared to the 60 tonnes of the IIIb4, it was now possible to tow 80 to 90 tonnes on the six percent gradient, since the power was now 300 hp instead of 250 hp. With two pusher locomotives, train weights of 240 tonnes were even possible.

Sectional drawing with dimensions

Die Lokomotive, August 1940

They replaced the IIIb4 on the Narenta railway, so that these were relocated to the route over the Komar Pass. But the IIIc5 was soon used there too. Since the two Mallet locomotives IIIb5 Nos. 751 and 752 had not proven themselves, additional engines with Klose supporting tenders were purchased in the years 1911 to 1919. This brought the number to 38, making it the most built rack locomotive. At the Yugoslav State Railways they were listed as class 97. The use of these locomotives ended there with the gauge change on the Narenta railway. The route over the Komar Pass was finally closed in 1975, which meant the end of the service life of the IIIc5. Four pieces are still existing today.

After several locomotives had been built in smaller numbers for the narrow-gauge lines in Austria-Hungary, the breakthrough as a standard locomotive was achieved with the IVa5. It was built as a tender locomotive with a 0-8-2 wheel arrangement, initially with a compound engine and later as a superheated simple engine. They are technically related to the Mh/Mv of the NÖLB. Some were built for the meter gauge for use in Hungary.

83-159 of the Banovići coal railway in June 2016 in Oskova

Friedrich Böhringer

Even after the end of the Austro-Hungarian monarchy, production continued for the railways of the SHS state and Yugoslavia. A total of 185 had been built by 1949, of which 169 were still in use in 1965. Even today, some are still in use on museum railways, including the Austrian Club 760. Two are used on the Banovići coal railway today, as they are more powerful in shunting than the existing diesel locomotives.

For the Steinbeis Railway in today's Bosnia-Herzegovina, the JDŽ needed six heavy narrow-gauge locomotives, which were supplied by Škoda in Czechoslovakia. In order to obtain sufficiently strong locomotives for the light construction of this forest railway, they had five coupled axles. They did not require any carrying axles and could generate a high pulling power with a wheel diameter of 800 mm.

When operations on the Steinbeis railway ceased in 1975, two locomotives came to the Banovići coal railway. Two more were erected as a memorial and another was placed in storage for eventual erection as a memorial. The number 1932 was bought by the Austrian club “Club 760” and has been used in the Czech Republic since 2009 as U57.001.