DRG Class 99.73–76
Encyclopedia
The German Class 99.73-76 engines were standard locomotives (Einheitslokomotiven
) in service with the Deutsche Reichsbahn
for Saxony's narrow gauge
railways. Together with their follow-on class, the DR Class 99.77-79
, they were the most powerful narrow gauge locomotives in Germany for the 750 mm rail gauge
.
The first series of 13 locomotives was built by the Sächsische Maschinenfabrik
, previously Richard Hartmann
, in Chemnitz
. According to the supply agreement, the Sächsische Maschinenfabrik was supposed to deliver more locos, but as a result of its bankruptcy and liquidation in 1930, this order was transferred to the Berliner Maschinenbau
AG (BMAG), previously Schwartzkopff. In 1928, seven locomotives were supplied by BMAG and another twelve followed in 1933.
The locomotives were very modern for their time, and were similar in design to the standard gauge Einheitslokomotiven. The engines fulfilled expectations; by double-heading
it was now possible to haul even very long (up to 56 axles) narrow gauge trains uphill.
In 1945, ten locomotives had to be given to the Soviet Union as war reparations
. At the same time, there was an enormous increase in the transportation required in the Erzgebirge mountains as a result of new uranium mines opened by
SDAG Wismut
. In 1952, in order to assist with the resulting shortage of locomotives, a similar follow-on class emerged, DR Class 99.77-79
, built by the VEB Lokomotivbau Karl Marx in Babelsberg
. At the end of the 1960s, the first Class 99.73-76 engines had to be retired due to boiler damage. Ten locomotives were given new, welded boilers and continued to work their original routes. In 1992, number 99 1760 was converted to oil-firing.
. The fixed third axle acted as the driving axle and had thinner wheel flanges to begin with. After 1945 its flanges were removed entirely to improve curve running still further. The wheelbase
was 3,000 mm initially; this was later increased to 4,000 mm.
As was typical on all Einheitslokomotiven, the engine had a Knorr feedwater preheater mounted tranversely above the smokebox
. The boiler
was fed using Friedmann exhaust steam injectors.
Because Heberlein
brakes were still partially in use at that time, the locomotives also had, on delivery, the necessary equipment for them, complete with guide rollers and winders (Haspel). The locomotive itself had a Knorr
compressed-air brake which was controlled by the vacuum brake
used for the train.
As the first engines were delivered in 1928, it was already planned, to replace the elderly funnel couplers by Scharfenberg couplers. So the first locomotives still had funnel couplers to begin; these were later swapped for the new couplings without any difficulty.
. On the hilly routes of Hainsberg–Kipsdorf, Cranzahl–Oberwiesenthal and Zittau–Oybin/Jonsdorf, however, these powerful engines soon became the main prime movers.
Today the Class 99.73-76 locomotives are stationed in Zittau
and Freital
-Hainsberg. One engine has also been on duty on the Lößnitzgrund Railway since the closure of the Weisseritz Valley Railway due to flooding (as at 03/2007).
Einheitsdampflokomotive
The German term Einheitsdampflokomotive, sometimes shortened to Einheitslokomotive or Einheitslok, means standard steam locomotive and refers to the steam engines built in Germany after 1925 under the direction of the Deutsche Reichsbahn-Gesellschaft...
) in service with the Deutsche Reichsbahn
Deutsche Reichsbahn
Deutsche Reichsbahn was the name of the following two companies:* Deutsche Reichsbahn, the German Imperial Railways during the Weimar Republic, the Third Reich and the immediate aftermath...
for Saxony's narrow gauge
Narrow gauge
A narrow gauge railway is a railway that has a track gauge narrower than the of standard gauge railways. Most existing narrow gauge railways have gauges of between and .- Overview :...
railways. Together with their follow-on class, the DR Class 99.77-79
DR Class 99.77-79
The steam locomotives of DR Class 99.77–79 were ordered by the Deutsche Reichsbahn in East Germany after the Second World War. They were narrow gauge locomotives with a 750 mm rail gauge and were built for the narrow gauge lines in Saxony. The locomotives were largely identical to the DRG...
, they were the most powerful narrow gauge locomotives in Germany for the 750 mm rail gauge
Rail gauge
Track gauge or rail gauge is the distance between the inner sides of the heads of the two load bearing rails that make up a single railway line. Sixty percent of the world's railways use a standard gauge of . Wider gauges are called broad gauge; smaller gauges, narrow gauge. Break-of-gauge refers...
.
History
Although there was already a very powerful locomotive for operations on the mountain lines in the Ore Mountains (Erzgebirge) of eastern Germany in the shape of the ten-coupled ex-Saxon Class 99.67-71, there was a further requirement for an even more powerful class. So it fell to the newly formed Reichsbahn railway division of Dresden to procured an Einheitslok with a 750 mm rail gauge. The Standardisation Office of the German Locomotive Union in Berlin-Tegel prepared the design for this class.The first series of 13 locomotives was built by the Sächsische Maschinenfabrik
Sächsische Maschinenfabrik
The Sächsische Maschinenfabrik in Chemnitz was one of the most important engineering companies in Saxony in the second half of the 19th century and the first two decades of the 20th century. Including its various predecessor businesses, the firm existed from 1837 until its liquidation in 1930, and...
, previously Richard Hartmann
Richard Hartmann
Richard Hartmann was a German engineering manufacturer.- Life :Richard Hartmann was born on 8 November 1809 in Barr, Bas-Rhin, the son of a tawer . In his Alsace homeland he learnt the trade of a toolmaker...
, in Chemnitz
Chemnitz
Chemnitz is the third-largest city of the Free State of Saxony, Germany. Chemnitz is an independent city which is not part of any county and seat of the government region Direktionsbezirk Chemnitz. Located in the northern foothills of the Ore Mountains, it is a part of the Saxon triangle...
. According to the supply agreement, the Sächsische Maschinenfabrik was supposed to deliver more locos, but as a result of its bankruptcy and liquidation in 1930, this order was transferred to the Berliner Maschinenbau
Berliner Maschinenbau
Berliner Maschinenbau AG was a German manufacturer of locomotives.The factory was founded by Louis Victor Robert Schwartzkopff on 3 October 1852 as Eisengießerei und Maschinen-Fabrik von L. Schwartzkopff in Berlin ....
AG (BMAG), previously Schwartzkopff. In 1928, seven locomotives were supplied by BMAG and another twelve followed in 1933.
The locomotives were very modern for their time, and were similar in design to the standard gauge Einheitslokomotiven. The engines fulfilled expectations; by double-heading
Double-heading
In railroad terminology, double-heading or double heading indicates the use of two locomotives at the front of a train, each operated individually by its own crew. The practice of triple-heading involves the use of three locomotives....
it was now possible to haul even very long (up to 56 axles) narrow gauge trains uphill.
In 1945, ten locomotives had to be given to the Soviet Union as war reparations
War reparations
War reparations are payments intended to cover damage or injury during a war. Generally, the term war reparations refers to money or goods changing hands, rather than such property transfers as the annexation of land.- History :...
. At the same time, there was an enormous increase in the transportation required in the Erzgebirge mountains as a result of new uranium mines opened by
SDAG Wismut
SDAG Wismut
The SAG/SDAG Wismut was a uranium mining company in East Germany producing 230,400 tonnes of uranium between 1947 and 1990. In 1991 it was transformed into the Wismut GmbH owned by the state of Germany which is now responsible for the recultivation of the former mining and milling areas...
. In 1952, in order to assist with the resulting shortage of locomotives, a similar follow-on class emerged, DR Class 99.77-79
DR Class 99.77-79
The steam locomotives of DR Class 99.77–79 were ordered by the Deutsche Reichsbahn in East Germany after the Second World War. They were narrow gauge locomotives with a 750 mm rail gauge and were built for the narrow gauge lines in Saxony. The locomotives were largely identical to the DRG...
, built by the VEB Lokomotivbau Karl Marx in Babelsberg
Potsdam
Potsdam is the capital city of the German federal state of Brandenburg and part of the Berlin/Brandenburg Metropolitan Region. It is situated on the River Havel, southwest of Berlin city centre....
. At the end of the 1960s, the first Class 99.73-76 engines had to be retired due to boiler damage. Ten locomotives were given new, welded boilers and continued to work their original routes. In 1992, number 99 1760 was converted to oil-firing.
Technical Features
These ten-coupled locomotives had carrying axles housed in a Bissel bogieBissel bogie
A Bissel truck is a very simple and commonly used way of designing a carrying axle on a steam locomotive to enable it to negotiate curves more easily. The design uses a single-axled bogie, usually known as a pony truck, whose pivot is towards the centre of the locomotive...
. The fixed third axle acted as the driving axle and had thinner wheel flanges to begin with. After 1945 its flanges were removed entirely to improve curve running still further. The wheelbase
Wheelbase
In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels.- Road :In automobiles, the wheelbase is the horizontal distance between the center of the front wheel and the center of the rear wheel...
was 3,000 mm initially; this was later increased to 4,000 mm.
As was typical on all Einheitslokomotiven, the engine had a Knorr feedwater preheater mounted tranversely above the smokebox
Smokebox
A smokebox is one of the major basic parts of a Steam locomotive exhaust system. Smoke and hot gases pass from the firebox through tubes where they pass heat to the surrounding water in the boiler. The smoke then enters the smokebox, and is exhausted to the atmosphere through the chimney .To assist...
. The boiler
Boiler
A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...
was fed using Friedmann exhaust steam injectors.
Because Heberlein
Heberlein brake
Heberlein brake is a continuous railway brake used in Germany that is applied by means of a mechanical cable. Train braking is therefore initiated centrally from the locomotive using a winder. This causes the brake clips to be applied on individual wagons, assisted by a servo system which makes use...
brakes were still partially in use at that time, the locomotives also had, on delivery, the necessary equipment for them, complete with guide rollers and winders (Haspel). The locomotive itself had a Knorr
Knorr-Bremse
Knorr-Bremse is a manufacturer of braking systems for rail and commercial vehicles that has operated in the field for over 100 years. The company also produces door systems for rail vehicles and torsional dampers. In 2009, the Group's workforce of over 14,000 achieved worldwide sales of EUR 2.761...
compressed-air brake which was controlled by the vacuum brake
Vacuum brake
The vacuum brake is a braking system employed on trains and introduced in the mid-1860s. A variant, the automatic vacuum brake system, became almost universal in British train equipment and in those countries influenced by British practice. Vacuum brakes also enjoyed a brief period of adoption in...
used for the train.
As the first engines were delivered in 1928, it was already planned, to replace the elderly funnel couplers by Scharfenberg couplers. So the first locomotives still had funnel couplers to begin; these were later swapped for the new couplings without any difficulty.
Operations
At the outset single locomotives were even used in the Thumer Netz and in WilsdruffWilsdruff
Wilsdruff is a town in the Sächsische Schweiz-Osterzgebirge, in the Free State of Saxony, Germany, with 13,743 inhabitants. It is situated 14 km west of Dresden . Near Wilsdruff there is a facility for high power broadcasting, the transmitter Wilsdruff....
. On the hilly routes of Hainsberg–Kipsdorf, Cranzahl–Oberwiesenthal and Zittau–Oybin/Jonsdorf, however, these powerful engines soon became the main prime movers.
Today the Class 99.73-76 locomotives are stationed in Zittau
Zittau
Zittau is a city in the south east of the Free State of Saxony, Germany, close to the border tripoint of Germany, Poland, and the Czech Republic. , there are 28,638 people in the city. It is part of the Görlitz district....
and Freital
Freital
Freital is the biggest town in the Sächsische Schweiz-Osterzgebirge district, in the Free State of Saxony, Germany. It is situated on the small river Weißeritz, 8 km southwest of Dresden.- Geography :...
-Hainsberg. One engine has also been on duty on the Lößnitzgrund Railway since the closure of the Weisseritz Valley Railway due to flooding (as at 03/2007).
Sources
- Erich Preuß/Rainer Preuß Schmalspurbahnen in Sachsen; transpress Verlag, Stuttgart, 1998 ISBN 3-613-71079-X
- Jürgen U. Ebel, Bernd Seiler: Die Baureihe 99.73-79 – Einheitslok auf schmaler Spur. EK-Verlag, Freiburg 1994, ISBN 3-88255-119-4
External links
- There is a relevant English-language forum at Railways of Germany