Can you see what is strange about this loco?
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Direct turbine drive?
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Turbine under thecab, behind the drivers?
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Dave, Yes direct turbine drive, like a PRR S2, although I think the turbine is on the pilot deck. And of course, you don’t hear “chuff-chuff” but “swooosh”
"In 1932, in conjunction with the Nydqvist and Holm company, Fredrik Ljungstrom developed a very successful 2-8-0 steam turbine locomotive, based on an existing conventional design, for freight traffic on the Grangesberg-Oxelsund Railway. (The TGOJ) The main purpose of the TGOJ was the transportation of iron ore from mines around and at Grangesberg to the Baltic port of Oxelosund, a distance of 159 miles (255 km). The first turbine locomotive proved to be more efficient than its conventional sisters; it could pull 1830 tons up a 1 in 100 gradient, and was reckoned to save 10% on fuel. All the engines were non-condensing, with a forward-mounted turbine and jackshaft drive. It was visited by Dr. Guy and William Stanier, and became the inspiration for the LMS Turbomotive.
Two further locomotives of the same class (M3t) were subsequently built. All were in operation until the mid 1950s when the line on which they operated was electrified. Two of the class are preserved in the Railway Museum at Grangesberg, Sweden.
The mines were worked out, and ore transport finally stopped, in 1990."
Ah, yes, the S2.
As anyone who has struggled with an out-of-quarter model steam locomotive can tell you, the drivers, rods, and axle boxes have to all be lined up just right that the fine thing doesn’t bind. It is not just the quartering of the driver crank pins, it is also getting the axle-box guides in parallel alignment. A lot of effort has gone, at least with the prototype, into optical or other means of finding that alignment and into axle-box shims or wedges to correct any misalignment.
That said, a jackshaft drive has long been of interest for a turbine locomotive such as this one along with early electric locomotives, diesels and even geared piston steam. Jackshaft drive is where the engine or electric motor rotates a shaft attached to the frame, the jackshaft, which is in turn coupled to the wheels by siderods.
The problem with jackshaft drive, on the authority of Wikipedia along with ALCo’s Alfred Bruce in his book on steam locomotives, is the potential for binding between the jackshaft that is fixed to the frame and the crankpin on a driver, where the driver is allowed to go up and down against its spring connection to the frame. This is not a problem with a direct rod drive from a crosshead because the driver crank going up and down will only cause small changes to the piston position in its stroke. This should only be a problem if the cylinder clearance volume were much less than used in steam locomotive applications.
There are a variety of imperfect remedies, which include using as long a driveshaft as possible to minimize this effect, some complicated linkages to allow the driver axle to change height with respect to the jackshaft with reduced bi
I think the same way they solved the angularity problem between the multiple drivers:
with a multi-piece, flexible side-rod system. It has been used on steam locomotives for over a century.
When one of the drivers goes up on a bump, and the others don’t, it is dealt with. In this case, we have a “driver” that doesn’t go up on bumps.
Ed
I spent a couple of weeks in Oxelösund (the “O” in TGOJ) back in 1986 well after the TGOJ was electrified. Didn’t realize at the time that the TGOJ was the home of the Swedish steam turbine locomotives covered by an article in the July 1967 issue of Trains. IIRC, the locomotives were in service for about 20 years.