BR Standard class - practice and performance

in 1952 , 70005 was used for controlled road testing on the S&C
the load was 850 tons , including 2 mobile test units . coal rate was 5600 lb per hr (!!) and a water rate of 36150 lb per hr.
the test lasted 1/2 hour ,from near Lazonby to Crosby Garratt .
the average DBHP was more than 2000 , peaking at 2500 .
the basic coal rate was 3lb per dhp hour

46225 was also tested around this time under similar conditions ,v/s 71000 , but the results were never made public . I wonder why

 

There is some information on these 46225 tests in 'LMS Locomotive Profiles - No. 11 - the Coronation Class' published by Wild Swan Publications, ISBN 978 1 905184 46 0.

 

dynamometer trace June 1951 70005. you will see the DBHP peaks at around 2500

 

This makes Britannia recorded most powerfull/mass british pacific,but the very peaky power going from sligthly downhill to uphill milepost 32.7 looks suspicious and not sustainable.

 

Latest scientific computer supported method has been employed and I read 2200 dbhp at 20.5 miles

WP_20180722_001[1] by Hermod posted Jul 22, 2018 at 4:33 PM

 

Same procedure as last time but bigger gain gives 2300 dbhp as max.
The Hengist thing with Duke cylinders could be quite something and easy to prepare compared to Tornado.

WP_20180722_003[1] by Hermod posted Jul 22, 2018 at 4:46 PM

 

There will be generations of kids looking at that photo and asking "WT* is that thing covering the screen?"

 

By duke cylinders do you mean smaller ones?.or so you mean smaller ones x 3? Or do you just mean Caprotti ? Caprotti
has been suggested but (unfortunately) rejected....

 

Two outside Caprotti of Duke /LMS 5mt size for my money as first try.
Will be interesting to se a 90 tons Clan locomotive pitted against a 107 tons Tornado

 

Say what ?
Since the Clans we're generally considered underpowered when it came to out and out slogging work, (though they ere only supposed to be class 6) having Smaller cylinders, and a valve gear which comes into its own for sustained high speed running makes very little sense, even with a full 250 psi boiler instead of a 225psi one

Interesting as it might be even if you can get 25 ihp/ tonne from the Clan - with the same size of train its not going to be the same league as a Peppercorn A1.

 

Between about MP 24 and MP 28 the average gradient is similar to that in the previous few miles or a bit easier and the cutoff is being lengthened, but the speed is falling. That makes sense only if the boiler pressure was falling significantly and the cutoff being lengthened to compensate.

 

With some luck both locomotives will be in mainline running order simultaneously and a match (one fireman each) can be arranged with TV coverage,betting etc.
Can surely pay the coal.
Bottom to top S&C with 300 ton behind?
Hengist has 17 tons less engine mass and this somehow compensate for lower adhession mass.

 

I might be missing something, but I struggle to see how a loco with 36sq ft of grate is going to outperform one with 50sq ft - whatever else you do, the starting point for power is how fast you can burn coal, and the clan straight away is at a significant disadvantage of having 28% less grate on which to do so.

Tom

 

disadvantage Tom. Well I could extol the virtues of the clan in terms of surefootedness on account of its comparatively low TE/ versus adhesive weight, but I don't think its worth it and instead will politely suggest that Hermod is just getting a bit silly now....

 

With one fireman and half an hour I do not know for sure.The best Caprotti steam consumption figure from Cox is 12.2 and best LNER is 13.4lbs/ihph

 

I am really struggling with this latest round of hypothesising to be honest.

The Clans were two cylinder, 6ft 2in locos with a smaller boiler, nominally 6MT. A step between the 5MT and 7MT 6ft 2in engines. They had a lower RA due to their different weight, and were always described as being underboilered.

Trying to squeeze power out of a 6MT equivalent to an 8P7F (Peppercorn A1) strikes me as similar to the debate over Scotsman's power classification when fitted with the 250lb boiler. In theory, the 7P6F was made up to a full 8P7F.

There's no doubting you could try and do that with a Clan. You then need to ask the question if what you get at the end of your design work is a locomotive that is actually a Clan, and if it is robust enough for the original design.

It was not thus with Flying Scotsman and that's why there was an incredible amount of rectification work to put right when the NRM and then Ian Riley & Sons went to overhaul her.

You can up the power, but chances are you'll make problems in other areas.

I would humbly suggest that the continual desire to change historical designs to an extent beyond their original parameters by a reasonable degree (piston valve to Caprotti on a clan? Which was never planned AFAIK by BR?) smacks of a desire to do something else entirely - design a new locomotive.

For which, I would happily support a thread to hypothesise about this all day long. But not in the Tornado thread.

 

P2 with Franklin valves and roller bearings all over is a more worthy opponent anyway.
It was just the realisation that Britannia was such a good locomotive that made me forget where I was.

 

Appreciate that. We can all get caught up in our thoughts

 

The Concensus from the Clan project people is that the original design is a little understated for a 6mt and if there is scope to run the new boiler at more than 225psi with little or no alteration to the build then that opportunity should be taken. Similarly the draughting was never really right, and if this is corrected to an extent that steam raising is consistently better the cylinder bore could be opened up a little.
In either case the max piston thrust would be no more than 5% above the original and subject to the approval of the 'VAB,/ NoBo.

A caprotti Clan, Brittania and even 9F are not far fetched considerations as the gear was considered a success on DoG and 5MT and deployment on further/pending orders of larger BR standard locomotives was expected* had such orders materialised. Had the Lentz(later Reidinger/Franklin) gear been sufficiently advanced to work for the original P2 its highly likely that the A4's would have had it.
( *Bond Cox Riddles et al.)
Unlikely however that the Thomson A2's /Pepp A1's would be so geared as Thomson would have been forced to choose something cheaper/simpler...

 

I am afraid my previous good mood has turned to dismay with more than a little bit of speculation dressed up as fact given.

Can appreciate that and certainly makes a lot of sense.

DoG was not considered a success when built. That is factual. The machine has proven its worth in preservation.

The Caprotti 5MTs were considered good machines but were not sufficiently superior to the standard piston valve machines to warrant any further building.

There is not, as far as I am aware, any evidence at all for a Caprotti 9F on the board in any way, shape or form.
Happy to be corrected.

There is no evidence to suggest this would have been case.

One side profile of the proposed A4 in the early 1930s includes P2 style cladding and lentz gear - this was dropped entirely and no further lentz gear locomotives were considered by Gresley for building, after Cock O' The North's rebuilding into a piston valve machine. Born out by the D49s turned out with conjugated gear and outside walschaerts valve gear.

There were difficulties obtaining spares for the Lentz fitted D49s during WW2 and this is why the sole D class 4-4-0 The Morpeth was rebuilt into a conventional two cylinder 4-4-0 with long lap travel valves and D11 inside cylinders and valve gear.

I do not believe Thompson was ever of the opinion that there were any advantages to the use of lentz gear over piston valves and walschaerts valve gear, whether under Gresley or as CME.

He had class B12/3 converted to piston valve from lentz gear when head of Stratford works and I rather suspect we could all agree that this was an unmitigated success for him and Gresley.

This is all, of course, material for a number of other threads entirely and still does not quite address 60163 Tornado...!