Bulgarian State 2-4-4-0 Locomotives in Bulgaria

Class 29.01 (Locobase 6794)

Data from the table presented on pages 386, 387 of the Groupe VI. - GTnie civil. - Moyens de transport. DeuxiFme partie. Classes 32 (Tome I), part of the series of Rapports du Jury Internationale of the Exposition Unverselle Internationale de 1900 Paris Exposition, hosted on the website of Le Conservatoire numTrique des Arts & MTtiers ([], Accessed 21 August 2005). See also L Renewal, "The Railways of Bulgaria", Cassier's Engineering Monthly, Volume 52, No 1 (July 1917), pp. 13-24 , esp Table of Principal Dimensions, p. 15; and See also "Bulgarian Railway Locomotives," Railway Engineer, Volume 33, No. 12 (December 1912), pp. 386-388. Works number was 2096.

The Jury report notes that the 1900 Exposition example was Maffei works #2096. For almost a decade after the original entry was prepared, the Exposition report was the only source of information about this design, Locobase could find nothing about this locomotive. Suspicion that it was simply a BB II Mallet with a leading truck was foiled by the larger dimensions in this design.

He supposed that it probably was a "one-off" because there are no accounts of classes of 2-4-4-0s in Germany. Indeed the only other Locobase entry (Locobase 1572) with this wheel arrangement and a separate tender describes a Hungarian class of 1905.

Then Locobase came across the Railway Magazine article of 1917 vintage, where appeared this single articulated. Photos show a slender boiler with a large steam dome forward of a square sand box. Behind them the external pipe led steam to the HP cylinders powering the rear set of drivers. It was wrapped in a square-section casing that looked like a large hoop holding down the rear portion of the boiler.

Renewal says that its trial on the Bulgarian lines was so unfruitful that it permanently soured the railway on Mallets of any size. He explains that while the permanent way was lightly built (axle loadings of 13-14 metric tons) and hilly and thus presumably suited to designs with a single boiler under several axles, the Mallet's only real advantage was in its ability to negotiate sharp curves. Since the Bulgarian alignments didn't require this, the engine's complicated layout and excess number of parts discouraged further trials.