The reference for locomotives and railcars
Württemberg Tss 4
German Reichsbahn class 9962
Germany | 1894 | 3 produced
Factory photo of the “Beilstein” with clearly recognizable lever mechanism
Factory photo of the “Beilstein” with clearly recognizable lever mechanism

The class Tss 4 referred to a small series of only three tank locomotives for 750 mm gauge, which was derived from the Ts 4 for 1,000 mm, which was also built only three times. They were used on the Bottwartalbahn from Heilbronn to Marbach, where they were used until they were replaced in the 1920s.

In order to improve the running characteristics on radii of up to 80 meters, the locomotives were designed with a complicated Klose chassis. In this case, only the second axle was fixed and the fourth axle, which was offset far to the rear, steered the first and third axles by a maximum of 31 mm each via a lever system. A lever system was also used to transmit power to the last coupled axle, which changed the length of the coupling rods depending on the curve radius. A special feature was the outer frame, because of which inside and inclined cylinders were also used. However, the coupling rods and the valve gear were outside the frame, since a lot of space was needed for the lever mechanism. The power was transmitted via Hall cranks and the water tanks had the cut-outs typical of Klose locomotives to provide enough space for the mechanics.

The three machines were given the operating numbers 11 to 13 and were named after localities along the 37 km long route. The latter were Großbottwar, Oberstenfeld and Beilstein. The Tssd 42 in a simpler Mallet design followed just five years after it was put into service, so no further Tss 4s were ordered. Nevertheless, the three machines remained in use and by the early 1920s were already showing clear signs of wear. At that time, after the establishment of the Reichsbahn, the Saxon VI K was also introduced on this line, so that the first machine was retired as early as 1923. The others still received the Reichsbahn numbers 99 621 and 99 622 and were retired by 1928.

Axle config0-8-0T (Eight-coupled) 
Gauge2 ft 5 1/2 in
Dimensions and Weights
Length26 ft 7 1/2 in
Wheelbase14 ft 9 3/16 in
Fixed wheelbase0 ft 0 in
Empty weight46,782 lbs
Service weight61,112 lbs
Adhesive weight61,112 lbs
Water capacity803 us gal
Fuel capacity2,205 lbs (coal)
Power sourcesteam
Estimated power268 hp (200 kW)
Optimal speed12 mph
Top speed19 mph
Starting effort14,723 lbf
Power Plant
Driver diameter35.4 in
Boiler pressure174 psi
Expansion typesimple
Cylinderstwo, 13 3/8 x 19 11/16 in
Grate area10.5 sq ft
Evaporative heating area642.3 sq ft
Total heating area642.3 sq ft
Calculated Values
steam locomotive
narrow gauge
tank locomotive
Klose engine
last changed: 04/2022

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