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BR “Britannia” Standards


jools1959
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2 hours ago, The Johnster said:

The 56s were criticised for poor, and noisy (grinding) brake performance when they were introduced in the 20s;

 

 

 

Sorry is this a typo for the the 70's? I thought the Class 56 were not use in the valleys due to their high RA and not their brakes (why 37/5 at RA5 were used instead). Given you mention HAAs and steam it is not clear which era you are referring to.

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37 minutes ago, Bomag said:

 

Sorry is this a typo for the the 70's? I thought the Class 56 were not use in the valleys due to their high RA and not their brakes (why 37/5 at RA5 were used instead). Given you mention HAAs and steam it is not clear which era you are referring to.

56 as in 56xx, the Great Western's take on the archetypal South Welsh 0-6-2T.

 

Jim

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14 hours ago, pH said:

C.J. Allen in “British Pacific Locomotives” quoted......etc.

 

pH, belated thanks for this reply - much appreciated.

I'm more familiar with the shenanigans involving early-BR diesels & electrics, the steam side of things seems no less convoluted though!

 

Also, for no apparent reason, I do have a soft spot for the Clans - maybe because however they came about, they didn't quite 'make it' and are overshadowed by the better-known classes.

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3 hours ago, keefer said:

Presumably he means 56xx Class steam locos?

He does, mea culpa.  The correct way to describe the locos is in the GW fashion, 56xx.  Collett’s response to the the South Wales 0-6-2T, which had developed as a consequence of the fairly short round trips to collieries, the simplicity of an 0-6-0 with a trailing axle to support a bunker with enough coal for the day’s work. 
 

The GW’s pregrouping response to Valleys work was to use panniers, small and large prairies, and 2-8-0Ts where the work warranted it, particularly where loaded trains had to be hauled uphill (Vale of Neath, Western Valley).  

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9 hours ago, SD85 said:

I agree with all that - things moved faster than anyone anticipated.

 

I didn't know that about the 9Fs, I was going on the basis that DB constructed zillions of class 50s and 52s which seemed to be rather similar in concept and worked mixed traffic across the system.


Not wishing to bring politics into this but the DB, DR and others 2-10-0’s were largely built during the war years and Germany’s version of a WD.

Edited by jools1959
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It was noted that the BR Clans were probably no match for the Bulleid Light Pacifics in terms of performance, but how did the Brits compare to the rebuilt WC's abd BB's? I suspect that the BR machines were more economical and reliable(like the Clans) , with the SR machines having the edge in performance, but is there any evidence or data of this?

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Not exactly comparative data on performance and economy as such, but there’s a very damning chapter on the Brits in OS Nock’s book From the Footplate, where he characterises them as ‘nobody’s babies’, adding ‘it was ironic that engines labelled as a British Standard should be so few in number at most of the sheds where they were based as to be regarded as non-standard’.  He gives multiple examples to support how their performance, other than in East Anglia, was consistently disappointing, concluding that ‘I cannot say that I ever had any journeys behind them that I could be enthusiastic over and this is reflected in the relatively poor availability of the engines for duty.  It is true that they worked very long mileages between successive visits to Crewe for periodic repairs, but they took a long time to amass those mileages.’  He then goes on to document the litany of mechanical issues that plagued the class, including the hollow axles, issues with cracks on the wheel seats that were very hard to fix due to problems in getting the roller bearings out, self-cleaning screens in smokeboxes that did not last from one boiler washout day to the next, and finally the catastrophic failure of the slide bar attachments that caused the derailment with many casualties on the S&C in January 1960.  His conclusion is that ‘with four separate drawing offices involved, I suppose it was really too much to expect complete success....(Roland) Bond felt that a Mark 2 Britannia incorporating all the lessons learned with the first lot, and with three cylinders, would have been a superb locomotive, but the edict of 1955 slammed the door on any such aspirations’.

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On 18/07/2020 at 00:14, jools1959 said:


Not wishing to bring politics into this but the DB, DR and others 2-10-0’s were largely built during the war years and Germany’s version of a WD.

Yes; the British equivalent was the WD 2-8-0 and 2-10-0, though it seems reasonable to suggest that Riddles' 9F was to some extent influenced by the Kriegsloks.

 

3 hours ago, DavidB said:

Bond felt that a Mark 2 Britannia incorporating all the lessons learned with the first lot, and with three cylinders, would have been a superb locomotive, but the edict of 1955 slammed the door on any such aspirations’.

Hmm.  There was a Riddles 3 cylinder pacific which was not exceptionally successful, but it was hobbled by construction errors in the blastpipes; rebuilt to correct specifications it has performed very well in a heritage role, but this is not directly comparable with daily traffic use.  A 3 cylinder version of a Brit would have been very similar to the rebuilt WC/BB locos, and I would suggest that Mr Nock was fully aware of this but fails to compare the classes.  Whether a rebuilt Bulleid light pacific was better in traffic than a Britannia is not within my knowledge, but the crews seemed to like them well enough.  

 

Horses for courses, I suppose; the Brits were, in the words of a Canton driver I spoke to in the 70s, 'good, strong engines' and would steam on a candle; so would the Bullieds.  The BR standards were all specified as 2 cylinder locos from the outset, and DoG is best regarded as a one off and not part of the standards at all.  Is a 3 cylinder light pacific better than a 2 cylinder one; yes, in some respects, particularly starting, but a 2 cylinder loco with a good boiler can pull well up hills under load.  Was the function of a mixed traffic light pacific fully understood in the UK, or was the association of pacifics with 8P work the cause of disappointment in the Brits, which were in fact a very good mixed traffic loco indeed.

 

As always in these discussions hard facts and comparative like-for-like performance figures are hard to come by, even in supervised loco exchanges under controlled conditions.  If you ran the same train with the same load behind a rebuilt Bulleid light pacific and then a Brit, on consecutive days with the same crew in the same weather, one loco would be better than the other, but the same result would be obtained from doing the same with different locos in the same class, and might be reversed if you did it again the following 2 days,  And the Brits and Bullieds were both locos that were controversial in any case, which would have further muddied the waters.

 

There were a lot of people of O.S.Nock's generation who had a poor opinion of the standards, in some cases simply because they were standards, designed to be jacks of all trades and masters of none, by a soulless nationalised bureaucracy manned by grey faced officials.  BR was subject to much of this sort of criticism, some of it justified but as much of it not, and it coloured some knowledgeable enthusiasts' views as well.  The glory days of the 30s, and the even more glorious days of the 1880s and the race to the north, were over, the bright and varied liveries and polished locos were as the snows of yesteryear, and much of this was cause for regret.  The fact that in the 1880s those shining polished locos were pulling trains with no heating and wooden seats, and were filthy and late by the 1930s is conveniently overlooked; old=good new=bad.  

 

At least Riddles, and to some extent Ivatt as well, tried to pull the railway into a realistic state in which it could cope with post war shortages, fuel, material, or manpower.

Edited by The Johnster
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I've always been under the impression that the intention behind making the Standards 2 outside cylinder designs was to simplify servicing. If you then put an additional cylinder and its associated valve gear between the frames you lose at least one of the loco's raisons d'etre. 

Edited by PatB
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The concept was to use the minimum number of cylinders required for the duties of the locomotive. This was being pushed to its absolute limit with the Britannias and it would, perhaps, have been better with three cylinders and a double chimney

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9 minutes ago, PenrithBeacon said:

The concept was to use the minimum number of cylinders required for the duties of the locomotive. This was being pushed to its absolute limit with the Britannias and it would, perhaps, have been better with three cylinders and a double chimney

It probably would have made a better loco but would have required the inside cylinder and associated valve gear and the necessity to examine and oil it during preparation, and all had been subjugated to avoid this. 71000 forced the use of three cylinders, but Caprotti gear was used to reduce the amounting of oiling of the Walshaert's linkages. The Caprotti gear for the inside cylinder was driven by a cross shaft from the left hand gear, but still needed attention to the inside big and little ends.

 

If Riddles had gone for three cylinders for the Brits, what gear would they have had? Interesting conundrum!

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I always wondered if Duke of Gloucester had been built “as designed”, would it been a huge leap against Stanier 4-6-2’s?  I think the loco was hamstrung at the building stage and therefore declared a failure during it’s BR lifetime.

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One of the issues with the Brits was how to drive them. When they went to Holyhead they were not liked by the crews who preferred the re built Scots and Patriots. Because of complaints a loco inspector travelled with the crews from Holyhead. He noticed that they were being driven on a partial regulator ( as per the Scots). On the next trip he suggested they use full open regulator and drive on the cut of. Result, the train shot out of the station! 
so like lots of new classes they needed a different driving style, drivers don’t like change!

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3 hours ago, Norton961 said:

One of the issues with the Brits was how to drive them. When they went to Holyhead they were not liked by the crews who preferred the re built Scots and Patriots. Because of complaints a loco inspector travelled with the crews from Holyhead. He noticed that they were being driven on a partial regulator ( as per the Scots). On the next trip he suggested they use full open regulator and drive on the cut of. Result, the train shot out of the station! 
so like lots of new classes they needed a different driving style, drivers don’t like change!

Peter Townends book 'LNER Pacifics Remembered' recounts a similar story about ex LMS men working the LNER A3s.

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19 hours ago, Norton961 said:

... He noticed that they were being driven on a partial regulator ( as per the Scots). On the next trip he suggested they use full open regulator and drive on the cut of. Result, the train shot out of the station! 
so like lots of new classes they needed a different driving style, drivers don’t like change!

 

15 hours ago, JeremyC said:

Peter Townends book 'LNER Pacifics Remembered' recounts a similar story about ex LMS men working the LNER A3s.

And another, Dick Hardy too wrote a most amusing memoir of an LMR conductor driver attempting 'turn and a half up and drive on partially opened regulator' on an A4, and complaining loudly that it wasn't as good as a Black 5. (Mr Hardy, tried beyond endurance, intervened!)

 

One of the most striking lessons not learned from 1948 BR exchange trials was that a long cut off and driving on the regulator was near universal in the UK; only the ex-LNER crews demonstrated the 'full regulator and drive on shortest cut off for the power requirement' technique.

 

On ‎21‎/‎07‎/‎2020 at 10:23, PenrithBeacon said:

The concept was to use the minimum number of cylinders required for the duties of the locomotive. This was being pushed to its absolute limit with the Britannias and it would, perhaps, have been better with three cylinders and a double chimney

There is no perhaps about it. Two cylinders for 6,000hp was fine on massively constructed North American locos, but as M. Chapelon much complained of, the weight limits imposed by European rail infrastructure hampered design for higher power outputs; by placing a  significant limit on frame strength. The Britannias literally worked themselves to pieces, with an 'exciting' range of failures that had not been seen on three and four cylinder machines of similar power output. 'Bill' DW Hardy gives an excellent digest of what he encountered while he had the GE allocated Britannias under his care. He determinedly kept them fit for work on intensive schedules which delivered high utilisation, but it doesn't make happy reading; and these were locos which only averaged 8 years old when they left the GE section in 1960.

 

Bye the bye, BR was quite correct to set limits on the use of the 9F in fast passenger service. Despite what was probably the best frame design ever accorded a large UK steam loco, they would have suffered severely if allowed to regularly run as fast as their power delivery permitted, for the same reason.

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31 minutes ago, 34theletterbetweenB&D said:

 

One of the most striking lessons not learned from 1948 BR exchange trials was that a long cut off and driving on the regulator was near universal in the UK; only the ex-LNER crews demonstrated the 'full regulator and drive on shortest cut off for the power requirement' technique.

 

It was not exactly an unusual driving technique on the Western either - some of the most respected Drivers always drove that way on the 4 cylinder engines.  Although reputedly the 'Castles' weren't so keen on full regulator working although I have ridden on them being driven that way and certainly up to 'c.60ish mph' there were no problems at all and it was a nice ride for the Fireman

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I would imagine that a Brit would produce more than 1,500 hp. Mike Notely reckoned that 2968 in climbing from Settle Jct. to Blea Moor, putting out 1,297 e.d.h.p. and an estimated 1,675 ihp, that from a considerably smaller engine. There are similar figures for Black Fives.

 

The theoretical full regulator / short cut off, however well it works with a multi-cylinder engine, but gives problems with a two-cylinder type, which became worse as mileage and wear increased. Running a worn out Black 'un below 30% was asking for trouble, and they weren't alone.

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Sorry, I think those figures are very speculative and don't include the context anyway. Personally I distrust any enthusiast's figures for power output, preferring indicator diagrams. Enthusiasts tend to over-estimate in their enthusiasm and all they are able to do is estimate anyway. I have often read Nock and Allen's articles and noted how different they were to the controlled tests done by BR. Best taken with a pinch of salt.

 

I agree that 'knocking' is a serious issue for two cylinder locomotives at low cut-offs and gets more serious as locomotives get run down; I believe the GW Saints had this problem too and it was one of the reasons why Churchward went to multi cylinders for later express passenger locomotives

 

The Britannias were intended more as a mixed traffic locomotive which is one of the reason's why they had a single chimney. SO Ell at Swindon was of the view, of which I'm not sure I agree, that single chimneys were always better than doubles, a view that seemed to change when Castles were modified!

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1 hour ago, The Stationmaster said:

It was not exactly an unusual driving technique on the Western either - some of the most respected Drivers always drove that way on the 4 cylinder engines.  Although reputedly the 'Castles' weren't so keen on full regulator working although I have ridden on them being driven that way and certainly up to 'c.60ish mph' there were no problems at all and it was a nice ride for the Fireman

I'd have posted something like this if you hadn't beaten me to it, Mike.

 

1 hour ago, PenrithBeacon said:

Don't think the power output of the Britannia's was anywhere near 6,000 hp!:DNearer to 1,500 perhaps.

We could have all sorts of debate about this.  Hp was measured for steam locos at Rugby testing plant on the rollers, and used as the basis for the powers specified for the prime movers of type 1, 2, 3, and 4 1955 plan diesels.  Thus class 5MT work was considered the remit of type 2 diesels, and class 7 or 8 work that of class 4s.  But it didn't work out like that in practice; Sir Brian Roberstson, who only ever flew a desk, noticed that D200 was inferior to a Britannia on it's inaugural run, suggesting that a nominally 7MT loco was capable of a better performance than one that had been designed to do the work of an 8P steam engine!

 

Now, this is not a precise science, or one would be able to use a GW 56xx to do the work of a Black 5, which it couldn't at much more than about 15mph, but then again a type 3 diesel had to be used, not a type 2, to replace 56xx on the Valley coal trains.  And skilled steam drivers could coax more from steam locos using techniques such as boiler mortgaging to temporarily give them a boost, whereas a diesel on full throttle could give no more than that (though I have seen some rather 'interesting' ammeter readings for short times, especially on overloaded 47s).

 

But something was clearly amiss in 1955, and decisions were made apparently which underestimated the amount of power a steam loco developed while apparently overestimating how much of the output of a prime mover could be put down on the rail.  8P pacifics were usually given figures of below 2k hp by Rugby, but in practice it took diesel locos of more than 2.5k hp to time 8P trains and 3.3k hp to equate to A4 performances, never mind improve on them.  Improvements, when they came, were achieved by limiting loads not by increasing power beyond mid 60s levels, and the successful HSTs used 8P equivalent power on 8 coach loads.  So a half hourly HST service of 8 coaches between Cardiff and Paddington took the same number of bums on seats as a Brit with 16 on, and achieved the increase in capacity by doing it in half the time and quadruple the number of trains, crews, and thus overheads.  

 

I believe that Ivatt got first generation diesels right first time with the twins. 1.5k hp to equate a Black 5 and 3k hp in multiple to equate a Duchess, or perhaps eventually a 9F.  A fleet of these could have answered all BR's needs well into the 80s and certainly until the advent of HSTs, backed up by dmus and 1k hp class 20 road switchers.  Yard shunting was in any case a proven field for pre-08 types by then.  BR, 7 years later, got it wrong at a fundamental level; the modernisation plan locos turned out ot be underpowered except 20s in pairs, and on a traffic not envisaged in 1955.  'Heritage' diesels still running are class 20s, already explained and a one-off, 31s, an underpowered 1955 plan failure rescued by replacing engines with 2nd generation prime movers, 33s, a second generation response to an underpowered type 2, 37s, ditto, and 47s, ditto type 4s.

 

Brits IMHO could put out over 2k hp (remember Sir Brian, talking about a brand new D200 in perfect nick) and probably did regularly on South Wales up Paddington trains.  Same goes for Castles with two more cylinders.

1 hour ago, LMS2968 said:

Mike Notely reckoned that 2968 in climbing from Settle Jct. to Blea Moor, putting out 1,297 e.d.h.p. and an estimated 1,675 ihp

This is, I contend, borne out by the inferior performances of the type 2s that replaced it; see above.

t t

2 hours ago, 34theletterbetweenB&D said:

Britannias literally worked themselves to pieces, with an 'exciting' range of failures that had not been seen on three and four cylinder machines of similar power output.

But they had.  3 cylinder Patriots, ball park same power output as a Brit, failed in the early 60s with cracked main frames as a result of having received more powerful boilers and double chimneys at rebuilds a decade or so earlier, and the same went for rebuilt Royal Scots.  GW KIngs, 8P BR power class, did the same thing with 4 cylinders, the power increase in this case being brought about by just the double chimneys and better superheaters.  

 

Steam, as remarked upon by yourself, was in the UK pushing the envelope of the amount of power that could be generated within existing loading gauge and axle loads permissible.  Brits had one of the best boilers in the game, and might have been more powerful with double chimneys, at the cost of down time under maintenance as they broke themselves to pieces maintaining Duchess timings!

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1 hour ago, PenrithBeacon said:

Sorry, I think those figures are very speculative and don't include the context anyway. Personally I distrust any enthusiast's figures for power output, preferring indicator diagrams. Enthusiasts tend to over-estimate in their enthusiasm and all they are able to do is estimate anyway.

Which is why I said 'estimated' and put the word in italics.

 

Even estimating from a dynamometer car isn't 100% accurate as there are estimates of the power consumption by the loco, and inaccuracy increases as the data becomes more vague. But it is a guide, albeit with some approximation.

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1 hour ago, The Johnster said:

But they had.  3 cylinder Patriots, ball park same power output as a Brit, failed in the early 60s with cracked main frames as a result of having received more powerful boilers and double chimneys at rebuilds a decade or so earlier, and the same went for rebuilt Royal Scots.  GW KIngs, 8P BR power class, did the same thing with 4 cylinders, the power increase in this case being brought about by just the double chimneys and better superheaters.  

A more recent example might be Flying Scotsmen where running it with a higher pressure boiler and oversize cylinders seems to have been responsible for the frame cracking discovered during its last overhaul.

Possibly the point '34theletterbetweenb&d' is making is that the Britannias suffered from their problems as originally designed and not after they'd been uprated.

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44 minutes ago, JeremyC said:

A more recent example might be Flying Scotsmen where running it with a higher pressure boiler and oversize cylinders seems to have been responsible for the frame cracking discovered during its last overhaul.

Possibly the point '34theletterbetweenb&d' is making is that the Britannias suffered from their problems as originally designed and not after they'd been uprated.

Until BR finally understood the issues at the bottom of the problem, fatigue cracks in frames originating from the top corners of the openings for the driving axleboxes were endemic in Gresley and other LNER locomotives, as well as LMS locomotives (including Black Fives). Both the LMS and the LNER kept spare sets of frame plates for various classes of locomotives as a consequence.

 

Jim

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