6202 Turbomotive/46202 Princess Anne

The Turbomotive was a modified Princess Royal Class steam locomotive designed by William Stanier and built by the London, Midland and Scottish Railway in 1935. It used turbines instead of cylinders. It was later rebuilt as a conventional locomotive 46202 Princess Anne.
The forward turbine had 18 rows of blading. Output was 2,400 hp (1,800 kW) at 7060 rpm, corresponding to running at 62 mph (100 km/h). Boiler pressure was 250 psi (1.7 MPa). The turbine was designed to operate into a maximum back-pressure of 2 psi (14 kPa), allowing a conventional double blast-pipe to provide the boiler draught, and eliminating draught fans, which always seemed to give a disproportionate amount of trouble.
The reverse turbine had 4 rows of blades. It was engaged by a dog clutch, activated when the reverser lever was set to "0". This was originally steam-operated by a small piston and cylinder.
Compared to some other experimental steam locomotives of the era such as the LNER Class W1, Turbomotive was relatively successful, showing a saving of coal compared to a normal reciprocating engine and no hammer blow on the track. Because steam turbines are highly inefficient when throttled (not a problem on steamships, where turbines typically run at constant output, but a major disadvantage for a railway locomotive which has to run at different speeds), power was instead controlled by turning on a different number of nozzles (from the six available) through which steam was admitted to the turbine. One disadvantage of the design was that the small reverse turbine only had sufficient power for manoeuvring "light engine" and the locomotive always had to be turned to face forwards in order to pull a train.
When a turbine failure occurred in 1949 it was considered uneconomic to repair during post-war austerity measures, so the locomotive was taken out of service pending a rebuild.
6202 was rebuilt as a conventional locomotive in 1952, using new mainframes and a set of cylinders of the same type as used in the "Coronation" class, and named Princess Anne. On 8 October 1952, after only two months in service, it was the train engine of the double-headed Liverpool and Manchester express involved in the Harrow and Wealdstone railway accident. The locomotive was taken to Crewe, where it was deemed beyond economical repair and scrapped. The destruction of No. 46202 led to the construction of BR Standard Class 8 number 71000, Duke of Gloucester.


6202 Shrewsbury


https://railway-photography.smugmug.com/LMSSteam/Stanier-Locomotives/Princess-Royal-Class/620246202-TurbomotivePrincess-Ann/6202-Turbomorive46202-Princess-Ann/i-8pBS7xv

6202 Turbomotive/46202 Princess Ann - Railway-Photography
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46202 Princess Ann Crewe station


https://railway-photography.smugmug.com/LMSSteam/Stanier-Locomotives/Princess-Royal-Class/620246202-TurbomotivePrincess-Ann/6202-Turbomorive46202-Princess-Ann/i-Ts4mSCb

6202 Turbomotive/46202 Princess Ann - Railway-Photography
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6202 Crewe May 1947


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6202 Turbomotive/46202 Princess Ann - Railway-Photography
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6202 Crewe 14th June 1947


https://railway-photography.smugmug.../6202-Turbomorive46202-Princess-Ann/i-nV7T4SF


6202 Turbomotive/46202 Princess Ann - Railway-Photography
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https://railway-photography.smugmug...202-Turbomorive46202-Princess-Ann/i-FdR3smg/A


6202 Turbomotive/46202 Princess Ann - Railway-Photography
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6202 Turbomotive/46202 Princess Ann - Railway-Photography
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railway photographs from the last 100 years



Neil

 

Excellent, Neil. Those smoke deflectors did little to add to the engine's appearance!

 

I wonder what 6202 sounded like? Here's a YouTube clip of a Swedish turbine loco, which might give some notion (credited as being filmed by Jan Ove Johansson):

 

I would love to see/hear a replica built..... Now to win the lottery first.
I know it is extremely unlikely to happen. probably never.

 

Dunno, worth doing it just to wind someone up...........................

 

It'd be a big chuffer that doesn't go 'chuff' - as I assume the steam feed to the turbine is continuous!

Well, does a model exist? Considering there's a wonderful model of GT3....

 

Seriously though of most of the 'experimental' locomotives never worked in service & the thermal efficiency of the 'Leader' was amazingly bad. This one however worked - as did the Swedish locos, its just a pity it never went into series production.

 

This is true, but it was built using (almost) standard Princess parts to allow a comparison to be made. Series production machines would probably have moved away from that, to smaller coupled wheels, since rpm would not be an issue; and possibly a larger diameter boiler which these would have allowed.

In reality, although 6202 was undoubtedly the most successful of the British experimental types, it's advantages over the standard Princesses were not sufficient to encourage series building.

 

What was the starting performance of the Turbomotive like? As I understand, there was a fixed gearing, linked by a clutch, between turbine and wheels. So I wonder how it started, since at zero rpm surely the turbine develops zero torque? But if you spun the turbine up to speed first, that’s a big stress on the clutch when you “engaged drive”, so to speak.

So I just wonder what it was like starting, and also whether there were any first hand records from drivers.

Tom

 

The drive was fixed, so the turbine had to start the train from zero rpm. It therefore had to be designed to produce torque over a large rpm range, which considerably lowered its efficiency at any speed. Earlier turbine locos in Britain were mostly turbo-electric, allowing a little more flexibility. For those who might not know, a turbine performs best at a high and fixed rpm, as in a power station or aboard a ship. This was one of the obstacles to its development by Metropolitan Vickers.

 

Although the Turbomotive & the Swedish turbine loco's worked unlike with the possible exception of Jawn Henry the turbo-electric ones

 

What a nice looking machine the rebuild was too... A crying shame it only survived 6 weeks before one of the worst accidents in UK rail history. Had it survived, one wonders what its performance would have been like as compared with the Princess Coronation class Pacifics...

Richard.

 

pics ,understandably , are scarce . here is one I came across recently .

there are very few comments on its performance but the few I have seen suggest it was pretty normal Princess Royal standard . with Coro cylinders and a single chimney it may have been loud .
I reckon , with no evidence , the single chimney was used in order to avoid fitting smoke deflectors ,which would have been very non Princess . whatever , the exhaust is lifting well clear in this pic .

 

Well it looks like 6201 is going nowhere soon. As some investment in this loco would be warmly welcomed someone could use this loco as a starting point & rebuild it as 6202. Only need one number changing and the colour could stay the same as well!!!

 

Looking that those photos at the top of this thread, assuming the smoke deflectors were added later (as opposed to removed) then I notice also that the cowling on the RHS was extended at about the same time. Any idea why?

 

Yes a model does exist, built by a Swiss gentleman by the name of Werner Jeggli.

He has documented the construction in a series of youtube videos which are really worth watching:

Part 1 -

Part 2 -

Part 3 -

Part 4 -


Keith

 

Additional oil pump to the reverse turbine.

 

There were major differences between 6201 and 6202, even after the latter was rebuilt with reciprocating drive. You'd need to replace the frames forward of the intermediate horn gap for a start.

 

Another experimental turbine loco was tried out by the Pennsylvania RR in the USA, that also seemed to work reasonably well but fell foul of the early change to diesel traction there.

 

How did 6202 compare with it's conventional siblings regarding coal and water consumption?