The reference for locomotives and railcars
Bavarian Pt 2/4 H
German Reichsbahn class 712
Germany | 1906 | 12 produced
First variant (No. 5001 to 5010)
First variant (No. 5001 to 5010)
Die Lokomotive, September 1906

For the cost-effective use of passenger trains on routes with low passenger volumes, the Royal Bavarian State Railways developed a locomotive that reached sufficient speed in both directions and could be operated by one man. The solution was a tank locomotive with a 2-4-2T wheel arrangement, which had a tipping device for loading the firebox with coal.

Second variant (No. 5011 to 5012)
Second variant (No. 5011 to 5012)
Die Lokomotive, October 1908

Thanks to superheated steam, it achieved adequate power and the coupling wheel diameter of 1,546 mm ensured a good compromise between tractive power and speed. There was a gangway from the driver's cab to the train and the front platform could also be reached via running boards with railings. The water tanks were designed to be narrower than the locomotive so as not to block the way.

Schematical drawing of the first version
Schematical drawing of the first version
Die Lokomotive, September 1906

A special feature of the chassis was that the first coupled axle was in a Krauss-Helmholtz bogie together with the leading axle, although there were only two coupled axles. This resulted in a fixed wheelbase of zero with very good curve guidance at the same time. The top speed was initially set at 75 km/h and later increased to 80 km/h. According to reports, however, they regularly ran in both directions at up to 90 km/h.

Twelve pieces were made, some of which differed from one another in several aspects. The Reichsbahn took over all of these and classified them as class 712. Some examples survived the Second World War and were used until 1948.

VariantNo. 5001 to 5010No. 5010 to 5011
Axle config2-4-2T (Columbia) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length35 ft 1 1/4 in35 ft 2 13/16 in
Wheelbase23 ft 11 3/8 in
Fixed wheelbase0 ft 0 in
Empty weight101,633 lbs
Service weight132,277 lbs128,970 lbs
Adhesive weight69,886 lbs69,225 lbs
Axle load35,274 lbs34,613 lbs
Water capacity2,113 us gal
Fuel capacity3,968 lbs (coal)
Power sourcesteam
Estimated power429 hp (320 kW)
Optimal speed14 mph
Top speed47 mph
Starting effort19,225 lbf
Power Plant
Driver diameter60.9 in
Boiler pressure174 psi
Expansion typesimple
Cylinderstwo, 19 5/16 x 21 1/4 in
Grate area13.2 sq ft
Firebox area60.3 sq ft
Tube heating area671.7 sq ft
Evaporative heating area731.9 sq ft
Superheater area210.9 sq ft
Total heating area942.8 sq ft
Calculated Values
steam locomotive
secondary line
tank locomotive
last changed: 01/2022

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