
Updated: 6 Oct 2001 | ![]() ![]() |
STALIN'S ENGINE: THE AA20-1. 1934
This notorious design was built at Lugansk Works, emerging in December 1934. [1] It became famous as the largest non-articulated locomotive in Europe, and in particular for having the most coupled axles in the world. A few countries produced 12-coupled designs, but nobody else tried 14. It was intended for heavy haulage on light (78 lb/yd) rails, with a modest loading of 20 tons per axle, on the Moscow-Donbass route. (The "20" in AA-20 refers to 20 tonnes per axle) It successfully made a publicity trip to Moscow in Jan 1935, but never entered service. No details are available of trial runs.
[1] Bell, writing in 1946, states that construction began as a 2-14-4 at the Krupp works in Essen, to a Soviet design, but was then transferred to Lugansk, where a leading bogie replaced the pony truck.
In (unsuccessful) attempts to get the AA-20 round curves, the middle three axles had flangeless wheels, and universal joints were include in the coupling rods between first and second, and sixth and seventh, axles.
Above: One of the very few pictures of the AA20-01 4-14-4 locomotive.
It was clear (though never publicly admitted) that the AA20 was a complete disaster. It spread the track, wrecked every set of points it passed over, and derailed almost every time it moved. Steaming was poor, and the locomotive too powerful for existing couplings and too long for the turntables.
Above: Side elevation of AA20-01. Note the enormous firebox for burning low-quality coal.
THE OR23-01 OPPOSED-PISTON STEAM LOCOMOTIVE. 1949
Below: The mechanism of OR23. The overhung crank on the centre axle reverses the direction of movement of one piston.
TEPLOPAROVOZ! THE 8000 2-8-2 OPPOSED-PISTON STEAM-DIESEL LOCOMOTIVE. 1939
Teploparovoz is Russian for "Diesel-Steam"; this loco used the Still Steam-Diesel system.
Below: The mechanism of 8000. The jackshaft on the right reverses the direction of movement of one piston.
The 8000 had many problems; for example, its 25 tonne axle-loading was too great for the track. It was stored in 1948 and never ran again.
TEPLOPAROVOZ! THE TP1-1 2-10-2 OPPOSED-PISTON STEAM-GAS LOCOMOTIVE. 1940
Coming soon.
TEPLOPAROVOZ! THE 8001 2-10-2 OPPOSED-PISTON STEAM-DIESEL LOCOMOTIVE. 1948
This was the third and last teploparovoz prototype to be built. It has been described as "almost a complete disaster".
Below: The mechanism of 8001. With eight cylinders, eight crossheads, and four extra rocking levers it does not look promising from the point of view of maintenance.
Bibliography:
After 1935 it was stored for 25 years at the Shcherbinka test facility and finally scrapped in 1960.
I assume the point of opposed-pistons was to obtain balance of the fore-and-aft forces, which would mean a reduction in wheel balance weights, and hence in hammer-blow on the track. There still seem to be heavy connecting rods going back-and-forth, so I'm not too convinced this was a sound plan. It seems to have been exclusively a Russian scheme.
This was the only conventional steam opposed-piston design; see below for steam-diesel versions.

Left: The opposed-piston OR23-01 steam loco of 1949. This experimental 2-10-4 was designed by N A Turkin and M N Anykeev, and built at the Oktober Revolution (OR) Locomotive Works at Voroshilovgrad. No more were built.
Left: Steam-diesel 2-8-2 opposed-piston freight locomotive No 8000, built 1939 at Voroshilovgrad Works. The name on the front is "Stalinets" ie a follower of Stalin.
See also the Kitson-Still Locomotive.
Here the outsides of the pistons were acted on by steam and the inner sides by internal combustion. Fleming states this system was later replaced by uniflow steam cylinders.
Confusingly, this locomotive was also called "Stalinets"
Left: Steam-diesel opposed-piston passenger locomotive No 8001, wheel arrangement 2-10-2, built 1948 at Voroshilovgrad Works.
"Locomotives", by A M Bell. 5th Edn. pub Virtue & Co, 1946
"Russian Steam Locomotives", Fleming. pub J.Marshbank 1960


