kaiserlich-Koeniglichen Oesterreichischen StB 2-6-4 Locomotives in Austria

Class 210 (Locobase 4686)

Data from "Express Locomotive, Austrian State Rys", The Locomotive Magazine, Vol XV [15] (15 February 1909), p. 30; and "Four-Cylinder Compound 2-6-4 Engine; Austrian State Railways", Railway Engineer, Volume 30, No 7 (May 1909), pp. 145-149 and June 1909, 188-190. (Thanks to Alexander Blessing for his 29 January 2022 email correcting engine and tender weights, tube diameter and length, Clench steam drier details, and builders as well as the cite to the RE article.) [] shows the work numbers as 1789, 1926-1930 from Floridsdorf and 356-359 from Bohemian Maschinenfabrik.

This four-cylinder compound passenger engine was the saturated-steam progenitor of the famous 310 Class of 2-6-4s (Locobase 1199) by Karl Golsdorf. Wikipedia notes their trailing load was impressive: 406 tons on the level at 100-110 km/h (62-68 mph). RE's 1909 report described the 2-6-4 layout as preferred by the Austrian State to the increasingly popular 4-6-2 as a way to distribute the weight of a larger grate and firebox over two axles rather than the single trailing axle of a Pacific. Front-end tracking used a Helmholz bogie setup that connected the leading driven axle with the front truck.

Alexander Blessing offered this succinct description of the Clench steam drier: "The tubes extended another 1.45 m [4 ft 9 in] through the Clench steam drier and terminated at the smokebox, giving a full length of 5.73 m [18 ft 9 1/2"). The Clench drier occupied the frontmost section of the boiler just behind the smokebox. It relied on the remaining heat from the tubes to dry out any latent moisture in the steam but did not function the same as the Schmidt superheater." kkStB estimated its drying surface area as 69.9 sq m (752 sq ft).

Golsdorf's compounding layout placed all four cylinders in line abreast and powering the middle driving axle. Low-pressure lay horizontally outside and high-pressure above the LP line and angled downward inside.

Each side's cylinders used one valve chest with tandem piston valves--nearly identical in diameter--mounted on a long spindle. The front valve served the HP cylinder, the rear valve taking the HP exhaust and supplying the LP cylinder. Editor Blundstone explained that Golsdorf wanted to use as few packing rings (of Wilhelm Schmidt's design) as possible. Each ring had a "number" of small holes to allow the steam to move to the back of the ring. He speculated that "whether much benefit is derived from these holes is somewhat doubtful."

Except for one lost in World War One, all of the class went to the Polish State Railways as their Pn 11.

For the superheated "masterpiece", see Locobase 1199.

Class 310 (Locobase 1199)

Data from A E Durrant The Steam Locomotives of Eastern Europe (Newton Abbot:David & Charles, 1972). confirmed or corrected by []. See also "New Locomotive Types, Austrian State Railways", The Locomotive, Volume XVII (15 July 1911), p.160; See also Gustav Reder (Michael Reynolds, trans), The world of steam locomotives (New York: Putnam, 1974), and O S Nock, Railways in the Years of Pre-eminence-1905-1919 (London: Blandford Press, 1971), Plate 22. (Thanks to Alexander Blessing for his 29 January 2022 email suggesting a change in builders and for noting the difference in valve design between the 210 and 310.)

According to Josef Pospichal ([]), the class's works numbers were

1911

Wiener Lokomotivfabrik Floridsdorf (Floridsdorf) 1989-1995, Lokomotivfabrik Wiener Neustadt (Wiener Neustadt) 5055-5061, Bÿhmisch-MShrische Maschinenfabrik Prag-Lieben (BMMF) 390-396, Staats-Eisenbahn Gesellschaft (StEG) 3790-3796

1912

Wiener Neustadt 5103-5111, StEG 3831-3839, Floridsdorf 2053-2056

1913

StEG 3876-3880

1914

Floridsdorf 2164-2168 and 2208-2213, StEG 3948-3949 and 3990-3995, BMMF 494-197

1915

StEG 4029-4031, Wiener Neustadt 5267-5269, BMMF 550-552.

Known as Karl Golsdorf's masterpiece, these express engines were preceded by ten Class 210, which used an inefficient Clench smokebox steam drier; see Locobase 4686 . As Class 310, they served Austrian (43), Prussian (7), and Polish (3) railroads.

OS Nock described the Adams bogie, which combined the leading truck and the leading drive axle. To allow the coupling rod between the first and second axle to work properly, the crank in the leading axle was cast as a ball on which the side rod was mounted. All four cylinders, inside and out, drove on the second axle. Nock's watercolor shows a tall engine with tapered boiler topped by a brass steam dome.

Hollingsworth (1982) comments that they weren't ideally proportioned as compounds (too much LP volume for the HP cylinders to fill) and the use of a two valves on one spindle for both the HP and LP cylinder meant difficult tweaking.

Alexander Blessing's review of illustrations of the 210 and 310 valve designs show that the 210's two valves were mounted on the spindle separated from each other. 310's layout had the two center shoulders placed at the ends of a single casting,. (See the photograph Blessing supplied at [])

Nevertheless, his valedictory is positive: Although the design never quite made use of all the boiler capacity, these were "...most imposing engines, and to build such a large locomotive for such a small weight was a masterpiece of design."

Gustav Reder agreed, noting that the chosen wheel arrangement offered good weight distribution and encouraged a smooth entry into curves. He claimed that there were 90 engines in the class (310.01-90) of which three went directly to Poland and seven more to Germany, thence to Poland in 1922.