Prussian State 4-6-4 Locomotives in Germany


Class Details by Steve Llanso of Sweat House Media

Class T16 (Locobase 7908)

Data from Christian Lindecke's Lokodex -- [], last accessed 25 October 2006 -- and the anonymous Wikipedia entry for this class at [].

Henschel produced this compound tank in response to a KPEV requirement to move 200 tons up a 1% grade at 75 km/h (47 mph) and reach 90 km/h (55 mph) on the flat. Its service area would be Thuringia. Although the locomotive itself was apparently successful, serving more than 20 years before being returned to Henschel for scrapping, it occupied a single-engine class. The KPEV instead chose to go with a simple-expansion design that appeared as the prolific T18. (See Locobase 1219).


Class T18 / BR 78 468 (Locobase 8039)

Data from [] -- the Hennings Eisenbahn site --accessed 28 December 2006. See Locobase 1291 for the main record on this successful Baltic tank.

This particular example (works number 20166) has enjoyed a long post-service career on display or in operation. It


Class T18 / BR 78.0-78.5 (Locobase 1291)

Most data from the US Military Railway Service Equipment Data Book for German Locomotives supplied by Allen Stanley from his extensive Rail Data Exchange in March 2004; and "Baureihe 78" in Albert Gieseler's Dampfmaschinen und Lokomotiven website at [], last accessed 26 September 2022. [] (a website that shows different preserved locomotives -- visited 2 March 2004, no longer active) presented different values for the heating surfaces; Locobase has created a second entry under BR 78 468 to record the differences, which may be due to a different builder than the one from which the MRS data are taken. See also K Miska's extensive writeup at [], last accessed 25 October 2006.

Entered service between 1912 and 1927. They were big and long and the low running board made the front truck wheels appear to be almost the same size as the drivers. The engine's wheelbase was perfectly symmetrical with even spacing ahead and behind the coupled axles, which themselves were equally spaced.

[] (a German steam locomotive parts supplier) says these were rated as capable of hauling a 560-short ton passenger train up a 2% grade at 90 kph. On the level, reported [], the T18 was popular with its crews and capable of both fast goods and fast passenger work.

NB: Most German locomotives showed tube heating surface area as calculated using the internal (fire side) diameter, which for this design came to 122.26 sq m (1,316 sq ft) and evaporative heating surface area as 135.2 sq m (1,455 sq ft). Locobase uses the external diameter to allow more direct comparison with locomotives of Anglo-North American origin.

In addition to the KPEV's order for 462, the Wurttemburg State Railway took 20 and the Elsass Lothringen Railway in Alsace-Lorraine procured 27. Vulkan produced all of the first 333 ordered through 1921 with later batches coming from Franco-Belge, Hanomag, and Henschel After the KPEV came under the DRG's purview in 1925, that nationalized system procured 127 more.

They came to France's SNCF as the TC and were highly valued on that railway as well. Miska says that Henschel delivered "several" T18s to Iraq's Baghdad Railway.

After World War II, the 508 surviving T18s served the Deutsche Bundesbahn (424), the Deutchese Reichsbahn of the DDR (53), and the Czech and Polish Railways (31 between them). One of the original 10 operated until 1969 and the last of the class was withdrawn in 1974.

Principal Dimensions by Steve Llanso of Sweat House Media

ClassT16T18 / BR 78 468T18 / BR 78.0-78.5
Locobase ID7908 8039 1291
RailroadPrussian StatePrussian StatePrussian State
CountryPrussiaPrussiaPrussia
Whyte4-6-4T4-6-4T4-6-4T
Number in Class1536
Road Numbers78 46878 001 - 78 528
GaugeStdStdStd
Number Built1536
BuilderHenschel & SohnHenschel & Sohnseveral
Year190419231912
Valve GearHeusingerHeusingerHeusinger
Locomotive Length and Weight
Driver Wheelbase (ft / m)13.45 / 4.1013.45 / 4.10
Engine Wheelbase (ft / m)38.39 / 11.7038.39 / 11.70
Ratio of driving wheelbase to overall engine wheelbase 0.35 0.35
Overall Wheelbase (engine & tender) (ft / m)38.39 / 11.7038.39 / 11.70
Axle Loading (Maximum Weight per Axle) (lbs / kg)44,092 / 20,00037,479 / 17,00037,479 / 17,000
Weight on Drivers (lbs / kg)131,175 / 59,500114,464 / 51,920114,464 / 51,920
Engine Weight (lbs / kg)271,168 / 123,000231,485 / 105,000237,440 / 107,701
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)271,168 / 123,000231,485 / 105,000237,440 / 107,701
Tender Water Capacity (gals / ML)3168 / 123168 / 12
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)5 / 5 5.50 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)73 / 36.5064 / 3264 / 32
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)68.90 / 175065 / 165065 / 1650
Boiler Pressure (psi / kPa)203.10 / 14174 / 12174 / 12
High Pressure Cylinders (dia x stroke) (in / mm)16.54" x 24.8" / 420x63022.05" x 24.8" / 560x63022.05" x 24.8" / 560x630
Low Pressure Cylinders (dia x stroke) (in / mm)24.8" x 24.8" / 630x630
Tractive Effort (lbs / kg)23,532 / 10673.9527,436 / 12444.7827,436 / 12444.78
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.57 4.17 4.17
Heating Ability
Tubes (number - dia) (in / mm)134 - 1.772" / 45134 - 1.772" / 45
Flues (number - dia) (in / mm)24 - 5.236" / 13324 - 5.236" / 133
Flue/Tube length (ft / m)15.42 / 4.7015.42 / 4.70
Firebox Area (sq ft / m2)140.96 / 13.10139.07 / 12.92
Grate Area (sq ft / m2)44.12 / 4.1025.72 / 2.3926.16 / 2.43
Evaporative Heating Surface (sq ft / m2)2057 / 191.201489 / 138.401603 / 148.90
Superheating Surface (sq ft / m2)473 / 44484 / 45524 / 48.70
Combined Heating Surface (sq ft / m2)2530 / 235.201973 / 183.402127 / 197.60
Evaporative Heating Surface/Cylinder Volume333.53135.85146.25
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation896144754552
Same as above plus superheater percentage10,66355945690
Same as above but substitute firebox area for grate area30,65930,248
Power L111,26412,063
Power MT650.85697.01

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