The reference for locomotives and railcars
Württemberg Hz
German Reichsbahn class 975
Germany | 1922 | 4 produced
97 504 in November 1986 in Kornwestheim
97 504 in November 1986 in Kornwestheim
Werner & Hansjörg Brutzer

The Reutlingen-Schelklingen railway line had a section between Honau and Lichtenstein, on whose ten percent incline the Fz class rack locomotives used up to one point of time were soon no longer sufficient. Therefore, the Württemberg State Railways ordered the new type Hz from Maschinenfabrik Esslingen, which was0 ten-coupled and was taken over directly by the Reichsbahn after it was founded.

The Hz shared some of the assemblies with the Tn and T 5 locomotives. The main difference was the Winterthur-type rack system, which was driven by two additional cylinders. Before entering the rack, the gear wheel had to be brought up to speed. To do this, the upper cylinders were briefly powered by live steam before switching to compound mode. From this point on, the lower cylinders of the wheels served as high-pressure cylinders, the exhaust steam from which flowed into the upper cylinders of the rack drive, which now acted as low-pressure cylinders.

After the first expansion, the steam had a larger volume, which was offset by the fact that all cylinders were of the same dimensions. This was compensated by the fact that the upper gear wheel rotated at twice the speed and the power transmission to the actual gear wheel for the rack took place only through a countershaft.

In the years 1922 and 1925, four locomotives were completed, which were put into service by the Reichsbahn as class 975. They all survived the war and were then taken over by the Bundesbahn. From 1952, two units received a modernization, whereby they received a new steel firebox, a reinforced frame, return springs on the laterally adjustable end axles to improve running smoothness and an increase in the coal bunker by one tonne. The first locomotive was retired in 1956 and the rest in 1962 after rack railbuses were introduced. Three of them are still preserved today.

Built1922, 1925
Axle config0-10-0RT (Ten-coupled) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Length38 ft 11 5/16 in
Wheelbase18 ft 11 9/16 in
Fixed wheelbase18 ft 11 9/16 in
Empty weight130,514 lbs
Service weight165,126 lbs
Adhesive weight165,126 lbs
Axle load33,069 lbs
Water capacity1,849 us gal
Fuel capacity8,818 lbs (coal)
Power sourcesteam
Indicated power838 hp (625 kW)
Optimal speed13 mph
Top speed31 mph
Starting effort40,861 lbf
with start valve49,033 lbf
Power Plant
Driver diameter45.3 in
Boiler pressure203 psi
Expansion typecompound
Cylindersfour, HP: 22 1/16 x 22 1/16 in
and LP: 22 1/16 x 22 1/16 in
Grate area26.9 sq ft
Firebox area135.6 sq ft
Tube heating area1,116 sq ft
Evaporative heating area1,251.6 sq ft
Superheater area455.3 sq ft
Total heating area1,706.9 sq ft
Calculated Values
steam locomotive
cog railway
tank locomotive
Eugen Kittel
last changed: 01/2022

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