6202 Turbomotive/46202 Princess Anne

allegedly she was better than a Duchess in most respects (but not going backwards) there are some logs of her work .
NB.- assuming you are talking about her time as the Turbomotive. = I have never seen a log for the rebuild .
obviously availability was an issue for a one of a kind loco

LMS2968 will probably give you a better answer

 

Don't even think about touching Lizzie . she is still a record holder and always will be

 

There was a very informative two-part article in the Meccano Magazine for November and December 1946, the sound (from the cab) was described as "a humming noise from the gears and literally a roar from the fire as the continuous purr of the exhaust whipped it into a seething mass of flame."

Also here is a very nice custom built 'O' gauge model of 6202.

Dave

 

As the Turbo, she was somewhat better than a standard Princes in terms of coal and water consumption, although not sufficiently so to mitigate against the extra maintenance costs. As rebuilt, there was little time to gather any real evidence. She had the improved cylinders and valve gear as applied to the 6220-on engines, but still had the smaller Princess boiler. I have read that she was a bit shy for steam, possibly a need for improved draughting was there, but there is little in the way of logs to go from.

 

Interesting - do you have the rest of that article? It seems to cut off rather suddenly!

Tom

 

That made me go take a quick look at what Meccano Magazines I have, more or less a complete sequence from 1948 through to the early 60s but only 2 from before 1948 - I must go through them and find the more interesting images and articles

 

Yes I do, I'll have a go tomorrow afternoon to post it all.

Cheers
Dave

 

Wasn't a link to either that article or a similar one posted on here a while back?

 

I'm no expert by any means, but I'm fairly sure that a steam turbine develops its maximum torque at zero rpm. Efficiency is a different matter though, and will peak well up the rev range.

I did suggest on another thread some time ago that if a new build was ever contemplated, it would be interesting to use a modern continuously variable transmission so that the turbine rpm could be optimised whatever the speed of the train. You could possibly incorporate reverse gear as well, removing the need for the second turbine.

Ok, it wouldn't be a replica, but I doubt you could ever build a true replica anyway. Could you really build a copy of the original multi-nozzle turbine, even if the drawings still exist? It would have to be the next class member, with improvements, cf. the P2.

As you say it will never happen, but wouldn't it be fun, albeit a bit pointless?

Dave

PS I see that tomorrow's Euro jackpot is £100m! ​

 

If your willing to put the money up Dave...! There's always someone on here willing to spend it for you!

 

That's correct steam turbines have high starting torque but low efficiency until they are up to speed. A lot of turbine locos seemed to suffer because the boiler was empty before the loco got up to an efficient speed.

The 3 surviving Swedish locos showed the way forward. They had 1 turbine with dog clutches to change direction and smaller wheels allowing the turbine to spin fast at moderate speeds.

The obsession with using condensing turbines seems to have held up development of the turbine locos. It was only when that idea was ditched did any real success come. Sadly it was too late by then, diesels and electrics were taking over.

Tim

 

That would be the rationale for using continuously variable transmission. The train can't keep to a constant speed, but the CVT should ensure that, as the train speed varies, the turbine maintains a constant rpm. I doubt that such systems would have been sufficiently well developed to have been considered for an application like this in the 193os.

Dave

 

OK. here is the complete two-part Meccano Magazine article, Laurie Earl even gets a mention, although he's referred to as Larry.

Cheers
Dave

 

@daveannjon Fascinating article - Thanks so much for posting it.

A couple of (general) operational details jumped off the page. One was the reference to what we today know as TSR as a 'slack' and the other concerned water troughs, with the comment about not getting a tenderfull due to their use by an immediately preceeding service. How I hope the GCR might some day install a trough for the purpose of demonstrating this lost art (and soaking passengers in the first few carriages who didn't shut their windows!).

I seem to recall a comment elsewhere that 6202 invariably carried a fitter on the footplate, as was the case on this run. Presumably, had Stanier persevered with turbines, this would have been addressed. The other thing which struck me was that the loco started it's train from Edge Hill on 3 steam jets, notching back to 2 once the train gained the west coast mainline. Given the train weight was estimated at 435 tons, you have to wonder how often all 6 jets were required.

The comment (at the start of the article) about a Black 5 assisting the train from the sidings back into into Euston (before the down run) rather confirms comments that the reversing turbine wasn't terribly useful!

I'm intrigued by the post from @Smokestack Lightning about Continuously Variable Transmission. This term is new to me and although pretty self-explanatory, so far as what it's for goes, does anyone have any detail on how it does what it does?

I liked the post from @meeee as well. IIRC, Stanier was well aware that smaller driving wheels would have made more sense, but the need for direct comparison with the 'Lizzies' dictated his course of action.

There's quite a bit about turbine locos on Douglas Self's (bloody marvellous) website, including the Pennsy 6-8-6 (serendipitously numbered 6200!) mentioned earlier in the thread. Here's the link to the page on 6202 (do navigate back via the orange "Loco Wing" button or, bit like trying to drink your way out of a brewery, you'll get so engrossed you'll never find your way back out!):
http://douglas-self.com/MUSEUM/LOCOLOCO/turbom/turbom.htm

 

Here is 100% of the worlds remaining steam turbine locomotive fleet in Grängesberg 2016. Non of them operable at the moment, No. 71 undergoing retubing.
The predecessors of the British turbomotive.

The original owner, the iron ore company of TGOJ, claimed that they were somewhat more fuel efficient and correspondingly more costly on maintenance. Making them overall par with their reciprocating counterparts. But that could be challenged. The conventional half-siblings, M3b (see B/W photo below), were 3-cylinder engines with low degree superheat and were known to have very cramped exhaust. The turbines had high superheat (400 C) and much better front end. At the time high degree superheat was used in Germany together with conventional machinery. Thus I firmly believe that a two cylinder loco with high degree superheat and good front end would have been at least as efficient as the turbines.

But this is for heavy iron ore trains where the speed is allowed to vary widely to even out the work load, as said above the turbine has very low efficiency at low speeds. In express service most of the work is done at high speeds, when the turbine is at its best.

 

To answer a few of these.

'Slack' is jargon term for a speed restriction, Temporary Speed Restriction (TSR) and Permanent Speed Restriction (PSR) are the correct terminology.

There is a pretty new and excellent book on this loco: The LMS Turbomotive From Evolution To Legacy, Jeremy Clements and Kevin Robertson, Crécy Publishing, ISBN 978-1-9093-2852-5. It covers 6202 in detail and most other turbines of all types to a lesser degree. It mentions the use of four nozzles, but not all six.

The reverse turbine was designed to move the loco only and was much smaller and les powerful than the forward turbine.

CVT basically uses a pair of pulleys with a continuous belt between them. By moving each side of the pulleys further apart or closer together, the belt acts on the pulleys at different heights, so varying the effective ratio.

 

Is that CVT the same principle which DAF used in their cars, it was called Variomatic transmission?

 

Very much so, but it's advanced a bit since then.

 

Also used by Rover in one of the Metro/100 cars.

 

Also by Motobecane (Mobylette mopeds) definitely by the late 50's. The engine block itself has suspended from a bearing and swung backwards through an arc as speed (a relative term in this context!) increased.