Bulgarian State 2-12-4 Locomotives in Bulgaria

Class 46.01 (Locobase 1590)

[] (viewed 18 July 2003). See also "A Massive Restoration in Bulgaria", Eastern Star (Journal of the New Europe Railway Heritage Trust), No 56 (December 2014), pp. 1-.; and diagram from Verlag Josef Otto Slezak, Vienna in 1990, show in [], last accessed 16 February 2024. Works numbers for new Polish builder were 201-212 in 1931.

These enormous engines--nicknamed "Mother Bear" by the Bulgarians--are among the few European engines with tractive power equal to the large North American behemoths that were their contemporaries. Working between Sofia and Pernik, they were entrusted with 80-car coal trains over a line with a ruling grade of 2.5%. Interestingly, the same boiler and grate was placed over two cylinders, as in these 12, and later over three. See the 1943 edition at Locobase 1591 for more details.

The Eastern Star account of 46.03's restoration said that the engine was on display for many years before tourist railway operators persuaded the BDZ to look over the locomotive at the Asenovo depot in Autumn 2013. The survey found that the locomotive would need only minor repairs. (Timing aided the effort considerably as the locomotive had been retired only six months after a major overhaul.) It was moved to Sofia in March 2014.

In October 2015, news reports noted the 46.03's return to service pulling three carriages over the weekend of October 17-18.

Class 46.13 (Locobase 1591)

Data from [] (viewed 18 July 2003). Works numbers were 11794-11801in 1942.

Although the first 12 2-12-4Ts were a success, it's likely that those two big cylinders (27.6" diameter) made for a certain "boxing" motion as they got up to speed. That's one explanation for this class, which had three smaller cylinders under the same boiler and grate. The three-cylinder motion, while more complicated and more difficult to maintain, would produce a more even sequence of impulses on those 6 sets of drivers. Certainly the higher weight and somewhat lower tractive effort reduced the slipperiness of the original design.

A photograph of this class shows a long boiler with low tanks forward, a short stack, six different bumps along the profile including two steam domes alternating with two sand domes, and a large vestibule cab in front of a plated-in coal bunker.The Krauss-Helmholz bogie, which combined the leading truck and the first driven axle, contributed to the design's flexibility as did the lateral movement of the 6th axle.