Jump to content
 

Please use M,M&M only for topics that do not fit within other forum areas. All topics posted here await admin team approval to ensure they don't belong elsewhere.

Imaginary Locomotives


Recommended Posts

  • RMweb Gold
17 hours ago, The Johnster said:

The Duke was two-cylinders, as well.    Damn good locomotive, especially after Swindon was removed from the picture. 

                          

                                                 ---------------------

 

No. the Duke was and is and has always been a 3 cyldiner loco except for the period when it lost one of the outside cylinders at Woodhams as a Science Museum exhibit to illustrate the workings of the British Caprotti valve gear.  Not sure what Swindon has got to do with it, loco built at Crewe to incorrect interpretation of the draugting arrangements and unpopular as a 'miner's friend' at Crewe North, not rectified until preservation rebuild.  Damn good loco following that, and one would be hard put to find any British pacific that was significantly better!

 

ISTR something like the double chimney was cast at Swindon (and was too small)?

 

 

EDIT: designed at Swindon but possibly not cast there according to the DoG website.

372882471_Screenshot2021-10-21at08_37_49.png.0dc37b711fee6b532650075e2e8ba90d.png

Edited by Corbs
  • Informative/Useful 3
Link to post
Share on other sites

  • RMweb Gold

I wonder to what, if any, extent the Swindon double chimney for the Duke was influenced by events a couple of years earlier concerning Ivatt 2MT moguls on the Mid Wales line.  The story is that the Brecon and Moat Lane drivers of this bucolic amble, about as far as you could get from blasting up Shap with 13 on, complained that the Ivatts did not steam as well as the Dean Goods they replaced, which resulted in Swindon taking the matter up with the LMR, who responded that perhaps fitting a copper capped chimney might solve the problem.  Swindon responded by redesigning the Ivatt blast pipe to the extent that they got a 2MT to haul a 20 coach test train at 60mph on the level between Swindon and Didcot. 
 

Swindon’s answer to the Duke’s requirement was to use 2 Dean Goods blastpipes, but the loco had been intended to use double Kylechaps, and while a similar arrangement worked well on the 9Fs, the Duke worked better with Kylechaps, one of several features proved in preservation.  
 

 

  • Informative/Useful 2
  • Interesting/Thought-provoking 1
Link to post
Share on other sites

  • RMweb Gold
2 hours ago, The Johnster said:

I wonder to what, if any, extent the Swindon double chimney for the Duke was influenced by events a couple of years earlier concerning Ivatt 2MT moguls on the Mid Wales line.  The story is that the Brecon and Moat Lane drivers of this bucolic amble, about as far as you could get from blasting up Shap with 13 on, complained that the Ivatts did not steam as well as the Dean Goods they replaced, which resulted in Swindon taking the matter up with the LMR, who responded that perhaps fitting a copper capped chimney might solve the problem.  Swindon responded by redesigning the Ivatt blast pipe to the extent that they got a 2MT to haul a 20 coach test train at 60mph on the level between Swindon and Didcot. 
 

Swindon’s answer to the Duke’s requirement was to use 2 Dean Goods blastpipes, but the loco had been intended to use double Kylechaps, and while a similar arrangement worked well on the 9Fs, the Duke worked better with Kylechaps, one of several features proved in preservation.  
 

 

 

This is really interesting and sounds a more reasonable explanation than hand-waving it as sheer bloody mindedness, apathy or stupidity.

  • Agree 3
Link to post
Share on other sites

2 hours ago, The Johnster said:

Swindon’s answer to the Duke’s requirement was to use 2 Dean Goods blastpipes, 

The smoke box arrangements on the Dean Goods had been upgraded several times over the years, so they were probably as current Swindon state of the art as any other. I note from GAs I have that blastpipe to bell dimension on 1940 Dean Goods GA and 1930 57xx GA is identical, as you'd expect it to be.  My knowledge of the complexities of front end design is minimal, but I note that the total volume of a set of Dean Goods cylinders is 46% of the total volume of the Duke cylinders, so maybe the Dean Goods casting was simply the right size?

Edited by JimC
  • Like 2
Link to post
Share on other sites

  • RMweb Gold
3 hours ago, Corbs said:

 

This is really interesting and sounds a more reasonable explanation than hand-waving it as sheer bloody mindedness, apathy or stupidity.

Not that sheer bloody mindedness, apathy, or stupidity were entirely absent at Swindon, or Crewe or Derby for that matter, or at Marylebone Road, in those days.  1954 was the final year before the Modernisation Plan, and one gets the impression that there were macro-political moves in progress to remove Riddles and the steam men in favour of modernist ideas.  Orders for several Standard classes were cancelled at around this time despite there not yet being any diesel replacements in the pipeline, or even planned yet.  71000 seems to have been built with a rather 'eyes off the ball' attitude and the Swindon chimney was a late substitution for the originally intended Kylechap, and preservation has highlighted several serious errors in the original transcription of drawings to the built locomotive.  Ashpan, blast pipe, firebox arch angle and so on badly affected the ability of the boiler to produce steam at an adequate rate unless large amounts of coal were consumed, and the loco was eventually put on to North Wales Coast Crewe-Holyhead work, fundamentally Royal Scot jobs, away from the big banks.

 

The idea is sometimes promoted that a class of Dukes could have been built for the top link 8P jobs, and that had they been built to the specs on the drawings they would have been more than capable of handling such work, but there is TTBOMK little evidence that this was ever considered to the extent of being cancelled.  A Duke in proper order could equal Deltic or AL1-6 performance, and beat it for short bursts (boiler mortgaging), but there were probably sufficient 8Ps in existence in 1954, some relatively recently built and some recently upgraded (Royal Scots and Kings).  The oldest in service were the A3s and Princess Royals, still with at least a decade left in them in 1954.

 

No crystal ball was available then to predict the frame issues that were shortly to beset the overpowered Royal Scots and the Kings, or the dire locomotive shortage on the WR 1961-2, which a couple of dozen or so Dukes might have relieved, so IMHO the reality was that in 1954 71000 was considered a one-off rather than a prototype, and that development of it was a waste of time.  Within a year the whole attitude had changed to 'diesel good steam bad', and within a relatively short time traffic dropped sharply as road haulage competition bit and private car ownership increased.  By the late 50s, railway investment was only reluctantly approved by the Treasury, and precedence was given to motorways and road improvements, and railway decline was the order of the day until the HST arrived and turned things around with timings that beat the bejaysus out of what could be achieved on the increasingly congested motorways of the mid 70s.

 

Fair to say that, by the late 40s, boiler design was pretty good, with Bullieds Peppercorns and the Standards able to raise steam as fast as the firemen could feed them and, under most circumstances, as fast as the driver could use it.  Basic principles would have been familiar to George Stephenson, but the efficiency had been honed to a very high degree of perfection.  The big issue were hammerblow, and poor driving technique based on outdated methods.  A 3 cylinder pacific with British Caprotti valve gear was a solution, but few drivers were willing to use the techniques and precision cutoff available to get the best efficiency out of the locomotive, and this did not help the already problem-strewn issues she (he?) had.  Caprotti locomotives needed a different driving technique that was not taught to the drivers, who were to some extent a small c conservative bunch of curmudgeons who reckoned they knew what they were doing and would have resisted it anyway.

  • Like 1
  • Interesting/Thought-provoking 2
Link to post
Share on other sites

So, here's another project I've been working on so far:

IMG_20211019_202215_7.jpg

IMG_20211019_202232_8.jpg

She may be rather toy-like, but it's certainly got character. I finally found a Hornby Toy Story 4-4-0 Chassis and decided to use it instead of the H Class chassis. The outside cylinders were removed and proper spoked wheels replaced the solid disc ones at the front. She's not quite finished but she is coming on a treat!

  • Like 4
Link to post
Share on other sites

  • RMweb Gold
5 minutes ago, tythatguy1312 said:

Correct me if I'm wrong, but I've heard the Duke was built to replace Princess Anne, the LMS Pacific destroyed in the Harrow & Wealdstone crash. Is there any truth to this?

I think that was the financial justification.

  • Agree 4
  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Gold

Correct AFAIK.  Princess Anne was a rebuild of the 'Turbomotive', and effectively a brand new loco less than 2 months old, and destroyed in the accident, though the remains spent some time at Crewe being assessed for repair.  It was eventually decided that there was too much damage, and she was written off, leaving an 8P sized gap in the LMR's allocation for the WCML.  Riddles had been arguing for an 8P and was therefore given the opportunity.  A 2-cylinder loco was initially considered in line with the practice of the day and the intention that no new multi-cyldiner designs were to be to be introduced as part of the Standard range.  It proved impossible to manage with 2 cylinders at the required power output within the loading gauge, and a 3 cylinder design emerged.  British Caprotti camshaft valve gear was adopted in order to be able to operate the inside cylinder valve gear from an idler shaft, overcoming issues experienced with Gresley conjugated, Thompson, Peppercorn, and Bullied valve gear, and to reduce the reciprocating mass and thus hammer blow.

 

It might have been easier, and in the event less unsuccessful, to build a Peppercorn A1 for the WCML, but Riddles had seen his chance and went for it.  The failure of the Duke may or may not have had an effect on the coup that removed him from his position within a year of the loco's introduction; my view is that the prevailing realpolitik of the day had already numbered his days in the big seat anyway.  It certainly didn't help his cause, though!

  • Interesting/Thought-provoking 3
Link to post
Share on other sites

  • RMweb Premium
4 hours ago, The Johnster said:

The idea is sometimes promoted that a class of Dukes could have been built for the top link 8P jobs, and that had they been built to the specs on the drawings they would have been more than capable of handling such work, but there is TTBOMK little evidence that this was ever considered to the extent of being cancelled.  A Duke in proper order could equal Deltic or AL1-6 performance, and beat it for short bursts (boiler mortgaging), but there were probably sufficient 8Ps in existence in 1954, some relatively recently built and some recently upgraded (Royal Scots and Kings).  The oldest in service were the A3s and Princess Royals, still with at least a decade left in them in 1954.

 

I think the video I posted shows The Duke making 2700hp for less than five minutes; how sustainable that was I don't know and remember that on "record-breaking" special runs there's usually more than one fireman, so hardly representative of what would be normal operation.  I certainly don't think it could match an AC electric though, even the "Old Ladies" AL1-5; remember that just like mortgaging the boiler on a steam loco, an electric loco has a continuous rating, a one-hour rating and a five-minute rating*, which is just long enough to climb from Tebay to Shap summit (where there is usually plenty of cool air stop the motors overheating.......).

 

Focussing on the ability to climb one part of the WCML as fast as the traction replacing it, misses the point of why they were being replaced.  One the Duke or any other steam loco got to Glasgow, chances are it went off to the depot having done its work for the day.  The AC electric meanwhile, worked back to London and probably did a fill-in turn to Birmingham afterwards, working for about 18 hours a day, probably three times the availability* of the steam loco.

 

*I know it's quite different from AL1-5, but on it's main line debut in preservation, 86101 hauled 13 coaches plus a dead 47 through Tebay at 95 and was still doing 75 at the top.  You can do that with a one-hour rating of nearly 8000hp.

**When they weren't catching fire, anyway.  The steam and diesel locos were internal combustion, the early ACs were external combustion.

  • Agree 3
  • Interesting/Thought-provoking 1
Link to post
Share on other sites

  • RMweb Gold
4 minutes ago, Northmoor said:

**When they weren't catching fire, anyway.  The steam and diesel locos were internal combustion, the early ACs were external combustion.

:D

I doubt, good though it was (is?), that the Duke would really be a match for an AC electric. Possibly it was on parity with a Deltic, but even a Deltic would likely be heading back to the Cross within an hour or so of arriving at Waverley. The thing about an AC electric is that it can produce that short term rating of nigh on 8000hp more or less on demand.

  • Agree 2
  • Interesting/Thought-provoking 1
Link to post
Share on other sites

  • RMweb Gold

There were certainly reasons to replace steam with diesel and electric traction that were not predicated on how well the locomotives could haul 13 up Shap, and 87s were doing this much faster than the Duke long before the record run featured in the video.  The Duke's performance was a record for steam, and better than any Class 40 or 47, or single 50 performance, and remarkable in it's own right for that and it's vindication of 8P steam power in the 1960s; shame it was 40 years too late...

 

Diesel and electric prep and disposal times, availability, labour intensivity, predictable reliability, crew comfort and cleanliness, and many other parameters are huge improvements on even the most modern and efficient steam locos, and post 1950s steam improvements from Porta to Red Devil or ACE 3000 have failed to make any impression on this undeniable and unavoidable fact.  I love steam, but cannot justify it on modern railways in normal service, and am sometimes a little irritated by those that want to turn back the clock and attempt this.  Kudos to the DoG team for their magnificent achievement with the loco, but don't try and tell me that it could have 'saved steam'.

  • Like 1
  • Agree 3
  • Round of applause 1
Link to post
Share on other sites

3 hours ago, LNWR18901910 said:

So, here's another project I've been working on so far:

IMG_20211019_202215_7.jpg

IMG_20211019_202232_8.jpg

She may be rather toy-like, but it's certainly got character. I finally found a Hornby Toy Story 4-4-0 Chassis and decided to use it instead of the H Class chassis. The outside cylinders were removed and proper spoked wheels replaced the solid disc ones at the front. She's not quite finished but she is coming on a treat!

Are you going to put bigger splashers over the rear drivers as well? :scratchhead:

  • Funny 1
Link to post
Share on other sites

I was going to suggest squaring up the splashers, putting in a lower beading strip to just above the wheel tops and painting and lining up to that. Then the box section above could have the ends of cross water tubes glued to it ala' early LSWR water tube boiler. Get a circle stencil to help with lining guides. :locomotive:

  • Like 3
Link to post
Share on other sites

  • RMweb Gold

I’m a bit worried about the rear driving axle, which goes through the ashpan or the lower part of the firebox.  The coupled wheels need moving rearwards so that this axle is behind the firebox, which aligns the front driven axle with that of the original single driver’s, and reduces the rear overhang.   Might mean the motor intruding into the cab, though.  

Edited by The Johnster
  • Like 1
  • Informative/Useful 1
Link to post
Share on other sites

On 20/10/2021 at 14:22, 313201 said:

Very feasible,  the Brittania locomotives were 2 cylinder pacifics

I realised that just after I logged off!

 

Why were two cylinders not used before the standards though?  Was it only feasible because of the higher boiler pressures?

  • Like 1
Link to post
Share on other sites

  • RMweb Gold

Pacifics in the UK were regarded as express passenger engines in the inter-war period, and it had been established by then that express passenger locos needed 3 or 4 cylinders in order to keep the outside cylinders within the loading gauge, reduce loading on the individual big end conrods and associated cranks, and provide a smoother ride for the passengers with less 

‘surge’. 
 

By the 1940s, ‘light pacifics’ were beginning to appear with driving wheels of a size more in line with mixed traffic work, though the reduction in driving wheel diameter was a trend anyway.  These were 3 cylinder engines, but the post-war labour shortages generated a need for locos that could be more quickly and easily prepped, so it was considered desirable not to have to go between the frames to oil around.  Swindon, bless ’em, carried on building 4-cylinder express locos regardless…
 

For this reason, the spec for Riddles’ Standards was 2 cylinders, and all of them were to be capable of mixed traffic work with the exception of the 9F, which acquitted itself pretty well on passenger duties,  Britannia and Clan pacifics were thus 2-cylinder mixed traffic ‘light pacifics’ of a general type that had been common on heavy outer suburban work for over 20 years in the US, but previously unseen here. 
 

71000 was to use standard components as far as possible, including the 6’2” driving wheels, but was conceived as an 8P express passenger loco.  In that sense, it is perhaps best considered as a one-off, by definition not a ‘Standard’ and never intended to be the prototype of a class.  

  • Agree 3
  • Informative/Useful 1
Link to post
Share on other sites

Which are pretty reasonable objections.   Even over here, width was a consideration.    Most of the American builders were in the North-East.   I forget which locomotive class it was, but at least one of the superheavy-types built for the Western states had to be delivered with its cylinders off, for clearance east of the Mississippi.   

  • Informative/Useful 3
Link to post
Share on other sites

  • RMweb Gold

The prime operating advantage of a pacific, derived from atlantics, is that a large boiler can be steamed from a wide firebox, able to burn lower grades of coal that may be more easily and cheaply available.  This is seen in larger 4-8-4 types used abroad as well, and the wide firebox advantage is carried through to oil burning.  The use of high grade Welsh steam coal is often correctly cited as one of the reasons the GW produced 4-6-0s instead of pacifics.  A large free-steaming boiler is a very useful thing if you want to run heavy passenger trains at high speeds over long distances, as it is able to produce steam to satisfy sustained high demand from the cylinders. 

 

Driving such a loco is a balance between using the steam and emptying the boiler of it, and sustained high output on a loco with large cylinders and an insufficiently large or inefficient boiler will lead to shortages of steam and loss of pressure, which can only be rectified to a limited extent by the fireman or mechanical stoker.  Of course, if high output is required for a short period, typically climbing banks, the boiler can be mortgaged and the mortgage paid off on the downhill run the other side of the summit.  OTOH, the combination of a large boiler with cylinders too small to handle it's output will lead to pointlessly wasted steam, coal, and water, and will be regarded as not successful, especially by the accountants and the firemen.

 

Express steam locomotives are particularly interesting because they are inevitably compromises between the demand for higher continuous power on one hand and the physical limitations of axle load, loading gauge, human firemen, or mechanical stoking on the other.  Getting this balance right, particularly with the UK demand for high power within route availability and loading gauge restrictions, is a fine line, as the operating costs of the loco have to be taken (literally) into account as well.  Express passenger work in the days befor motorways and high percentages of car ownership was a sound earner for the railways, but the locos still had to earn their living; the purpose of a railway is to provide profit for it's shareholders and carrying freight or passengers is a secondary consideration and only a means to that end.

 

Similar interesting compromises can be found in Blue Riband Transatlantic Ocean Liner design, where the space allocated to engine rooms and machinery has to compete with space for service areas, passenger cabins and large luxury areas for fisrt class in a hull shape suitable for 30knot+ all weather operation, and in post WW1 battleships, where an elusive optimum balance of speed, armour, and firepower had to be found within the treaty tonnage limits, though not all countries played the game strictly to the rules. 

  • Informative/Useful 3
  • Interesting/Thought-provoking 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...