The engines of DR Class 99.23 are
metre gaugetank locomotives, that were procured by the
Deutsche Reichsbahn (DR) in
East Germany from 1954 to 1956. When they entered service they had operating numbers 99 231–99 247. Today they are numbered 99 7231–99 7247.
History
A total of 17 locomotives were bought by the DR between 1954 and 1956 for the railways of the
Harzquerbahn and
Brockenbahn, and for the line from
Eisfeld to
Schönbrunn to replace much of the very old fleet. 4 locomotives were built for the USSR in 1956, whatever happened to these 4 engines is unknown. The first seven units (99 231 to 99 237) were originally equipped with two
Krauss-Helmholtz bogies. Due to problems with curve running, the engines in the second series were given
Beugniot levers between the first and second
coupled axles in addition to the Krauss-Helmholtz bogies.[1] (according to other sources also a
Schwartzkopff-Eckhardt II bogie[2][3][4][5]). The locomotives of the first series were subsequently modified with Beugniot levers, some in the early 1960s, others in 1973/74 (on the Harz lines). The thinner wheel flanges of the driving wheels were completely removed later in order to achieve better curve running. Certainly the engines in the second series did not have a rigid wheelbase.[2]
These Neubaulokomotiven were a fully welded evolutionary development of the standard locomotives (Einheitsloks) of the
DRG Class 99.22. In contrast to those, the 99.23-24s had mixer-
preheaters and
plate frames. However, the latter caused maintenance difficulties from the outset due to cracks and distortion. To date 10 locomotives (the present-day 99 7232, 7240, 7245, 7239, 7236, 7234, 7237, 7241, 7243, 7247) were equipped from 2004 onwards with a new, redesigned plate frame and 5 of them (99 7232, 7240, 7245, 7239, 7236) with new, welded, steam
cylinders. More should follow. The 17 DR-engines all still exist and are based in the Harz; some however are no longer working.
The 17 German engines were converted to primary oil-firing between 1977 and 1983 and are, together with the DRG Class 99.22, the most powerful narrow gauge German steam locomotives ever to have been built. They were later converted back to coal-firing and are primarily used on the line up to the
Brocken from
Wernigerode.
Their operating numbers changed from 99 231 et seq to 99 7231 et seq on the introduction of computerised numbers in 1970 and then again to 99 0231 et seq on conversion to oil-firing. The computer numbers are still valid, because the
HSB retains those allocated in the
1970 DR renumbering scheme.
The locos can carry 4 tonnes (4 long tons; 4 short tons) of coal and 8,000 litres (1,760 imperial gallons; 2,113 US gallons) of water.
Locomotives
99 7231: out of service since 2001
99 7232: working, new frame
99 7233: out of service since 1999
99 7234: working, new feame
99 7235: out of service since 2020
99 7236: working, new frame
99 7237: working, new frame
99 7238: working
99 7239: working, new frame
99 7240: working, new frame
99 7241: working, new frame
99 7242: out of service since 2010
99 7243: working, new frame
99 7244: working, undergoing conversion to oil-firing