Imaginary Locomotives

[PhilJ W]

9 hours ago, Miss Prism said:

 

https://didcotrailwaycentre.org.uk/shopimages/2. Hurricane 2 crop 1800.jpg

 

(as explored in October 2021 Going loco blog)

 

The boiler/tender looks identical so could be attached to any motive unit. Quickly exchanging motive units?

[rockershovel]

12 hours ago, rodent279 said:

Yeah. Close, but no cigar!

To be fair, the actual designers of these locos (as well as Brunel's team responsible for accepting the design) were not alone in failing to understand the importance of adhesive weight. Cramptons disregard the principle but were quite successful for a while. 

[DenysW]

I'm intrigued by what loco Gooch would have  produced if he'd been asked to win the Parliamentary gauge trials totally decisively, not just by being visibly better. Thus using the bigger Great Western loading gauge to its fullest, not just the track-gauge. A long-boilered Stephenson-built 2-4-0 with 8 ft drivers and 24 " diameter, 24" throw pistons? Or just an Iron Duke 2 years earlier?

 

I think he'd have probably lost anyway because of the number of people he must have annoyed by having the gauge requirement dropped from the Great Western Act on rather specious grounds. But Ixion clearly wasn't so much better that its superiority couldn't be ignored.

[whart57]

1 hour ago, rockershovel said:

To be fair, the actual designers of these locos (as well as Brunel's team responsible for accepting the design) were not alone in failing to understand the importance of adhesive weight. Cramptons disregard the principle but were quite successful for a while. 

 

Crampton designed locomotives with a different goal in mind, namely achieve higher speed without creating more instability through piston reciprocation. They worked with the light trains of the 1840s but once rail travel became popular and trains heavier then the loss of adhesion became a serious issue.

[rockershovel]

14 minutes ago, whart57 said:

 

Crampton designed locomotives with a different goal in mind, namely achieve higher speed without creating more instability through piston reciprocation. They worked with the light trains of the 1840s but once rail travel became popular and trains heavier then the loss of adhesion became a serious issue.

Quite so. A lot of fundamentally flawed concepts can be made to work if the required performance is low enough. 

 

Which isn't to say that Crampton was wrong in the concept of the large single driving wheel. More conventionally engineered examples had a long and successful career pulling light, fast trains, for as long as such trains were viable.

 

The REAL weakness of many "primitive" and Georgian designs was their lack of design potential. The Americans got one thing right from the beginning - the requirement for good, stable handling. This led them to the 4-2-0 at an early stage and hence, the 4-4-0 which was hugely successful 

Edited December 4, 2021 by rockershovel

[Flying Pig]

4 hours ago, John Besley said:

They also seemed to swell up as they burnt initially like a cauliflower - and the sweet smell of Welsh coal never to be forgotten.... ahh

 

Ahh the sweet smell of about a thousand mutagenic constituents.  No wonder the harmonies at the Arms Park were so lovely when half the singers had two heads.

[whart57]

1 hour ago, rockershovel said:

The REAL weakness of many "primitive" and Georgian designs was their lack of design potential. The Americans got one thing right from the beginning - the requirement for good, stable handling. This led them to the 4-2-0 at an early stage and hence, the 4-4-0 which was hugely successful 

 

The quality of American track had a lot to do with that.

[whart57]

To get back to Garratts. Mention of the Beyer Peacock patent made me wonder whether my statement of no British motive power in Thailand from the end of deliveries of the E class to the arrival of the Class 158s 75 years later was correct.

 

It was. The small class of Thai Garratts were supplied by Henschel. They were bought in the mid 1920s for the line to the North East. This line had gradients of up to 1 in 42 along a 30 mile section. The line was originally standard gauge and regauged some years before the Garratts arrived. In 1913 a pair of 0-10-0s had been bought from Hanomag to handle freight traffic through the mountains. Originally standard gauge they were regauged c1920, but they were not up to the job.

 

Thai railway management were impressed with some Garratts the Burma railways had and ordered 2-8-2+2-8-2 machines from Henschel. The specification was to haul 530 tonnes up a 1 in 42. The Henschel Garratts did that but the problem was with the firebox, it proved difficult to fire in order to get enough steam to feed four cylinders. I'm not sure whether Henschel's designers fully realised the extra challenge of wood burning. A second batch of two machines had a 60% increase in grate area to cope with wood burning

 

These Garratts lasted until the end of steam in Thailand but spent their days on this mountainous bit. The Thais didn't buy any Garratts for use elsewhere even though they did buy some impressively large meter gauge Pacifics and Mountains (4-6-2 and 2-8-2)

[rockershovel]

1 hour ago, whart57 said:

 

The quality of American track had a lot to do with that.

Also that the Americans bought in their early locomotives. The "primitive" phase bypassed them almost entirely. Their first original design - the bar-frame 4-2-0 -derived from experience of early models which were at least, sufficiently usable to have been built commercially 

Edited December 4, 2021 by rockershovel

[DenysW]

A reminder that the UK manufacturers were indeed creative, but not always successfully. Armstrong Whitworth's locomotive was about an 8F for power but had the starting tractive effort of a steam 3F, wasn't successful and was scrapped in a year or so. But it's got everything: articulation, driving wheels under the tender, turbine-electric, steam condensing, the lot.

 

[rodent279]

2 hours ago, DenysW said:

A reminder that the UK manufacturers were indeed creative, but not always successfully. Armstrong Whitworth's locomotive was about an 8F for power but had the starting tractive effort of a steam 3F, wasn't successful and was scrapped in a year or so. But it's got everything: articulation, driving wheels under the tender, turbine-electric, steam condensing, the lot.

 

I've always thought that's a handsome machine, in its own way. Shame it wasn't more successful, I think the concept is interesting. Wonder if a fleet of such machines, had they been more successful, would have been useful on SWales coal trains, maybe with rheostatic brakes? Maybe even with feedwater pre-heaters powered by the rheostats?

[Dr Gerbil-Fritters]

54 minutes ago, rodent279 said:

I've always thought that's a handsome machine, in its own way. Shame it wasn't more successful, I think the concept is interesting. Wonder if a fleet of such machines, had they been more successful, would have been useful on SWales coal trains, maybe with rheostatic brakes? Maybe even with feedwater pre-heaters powered by the rheostats?

 

It's not a turbine electric, but might give some suggestions to a turbine that was designed for coal hauling and was successful...

 

 

[rodent279]

6 hours ago, Dr Gerbil-Fritters said:

 

It's not a turbine electric, but might give some suggestions to a turbine that was designed for coal hauling and was successful...

 

 

Yes, nice machines, I'd love to go to Sweden and see the preserved one in action.

[DK123GWR]

Disciples of Swindon, cover your eyes. The ideas contained within this post are heretical and will defile your mind with their filth. You have been warned.

 

I've been doing some thinking regarding the locomotive for heavy, continuously braked freight trains. I started by suggesting a 47xx could be suitable, but tonight I wondered what you might end up with if you decided that wasn't enough (basically, I got bored and wanted an excuse to dream up something far too big fun, rather than wondering about using side-tanks instead of panniers, and weighing up whether it would be better to start from a model of a pannier or from an 0-6-0 tender engine with the same boiler).

 

The idea is something along the lines of a 4-8-0 with 5 ft 8 inch driving wheels (so a 47xx with an extra leading axle) underneath a Standard No. 12 (King) boiler, which has the same diameter at each end as the 47xx's Standard No.7, but is 14 inches longer and a larger firebox (18 inches longer, with an extra 4ft^2 (I think) of grate area). I don't know whether 2 or 4 cylinders would be more suitable. The front bogie would be entirely inside framed because:

1) The King bogie was a bodge which I have been led to believe could have been avoided (in hindsight at least) by making other changes

2) I've always thought that it looks rather ugly, and causes the loco to look unbalanced (I was hesitant about writing this, but as it is certainly the lesser of the two sins I have committed today, why not?)

 

I'd be interested to know why this beast is so impractical (I know I might be pushing my luck with weight limits, but I'm hoping the extra driving axle vs a King will help in this regard) and what a more sensible solution to the problem might be. Also, please don't burn me at the stake - I love panniers really, it was just a thought experiment you see...

[Miss Prism]

You mean a bit like this (which has a Star 4-cylinder front end) ?

 

The matter is discussed in 

 

[JimC]

A 4-8-0 chassis under a King boiler seems feasible enough without actually drawing it.

You might enjoy 'Swindon Apprentice' by AE Durrant. 'Dusty' Durrant trained on the (G) WR in the 40s and 50s and then worked mainly overseas. His book is a mix of his time as an apprentice and in the drawing office at Swindon, interspersed with tales of his trips round Britain and Europe photographing steam, plus drawings of the mighty locomotives he drew up in idle moments. Its pretty readily available secondhand I think. 

[AlfaZagato]

I wonder if the extra axle would have taken the King down to Red availability?

[Corbs]

 

Sounds like this from 2018.

 

Incidentally I had been wondering about a smaller wheeled version but someone pointed out that you can't have a 4 cylinder loco with small driving wheels using the Swindon layout because the conrods for the inside cylinders would hit the rear bogie axle - they have to be large wheels with driving axles up high for the rods to clear it.

 

 

For good measure here it is alongside some other Hawkswerents - a Hawksworth 4710 and a Borough-Class.

 

[JimC]

3 hours ago, AlfaZagato said:

I wonder if the extra axle would have taken the King down to Red availability?

Potentially yes. The nominal King adhesive weight was 22.5 x 3 =67.5. Divide by 4 is 19.125 against 19.5 for the red limit. 5'8 wheels would save a bit too. 

[whart57]

What would the purpose of a "Super-King" 4-8-0 be? In most of the world the  4-8-0 arrangement was for freight locos, and a lot were built for the meter and 3'6" gauges. The exception would appear to be a class of 4-8-0s designed by Chapelon for the SNCF, which were express passenger locomotives. The SNCF 240s (from the European classification for a 4-8-0) were specifically designed to take heavy trains up long gradients, and they didn't actually last that long.

 

We could ask whether this Super-King 4-8-0 is only feasible because of the GWR's aversion to trailing pony trucks. Most other railways needing a fast eight coupled loco would build Mountain 4-8-2s which have more space for a humungous firebox.

[Corbs]

My idea behind it was to keep the Welsh Steam Coal mines in business by using as much of it as possible.

[sir douglas]

Drawing of an unbuilt 4-8-2 class for Nigeria, at 12'6 tall including head lamp it would fit British loading gauge if modelled as SG and with 4'8" wheels it could be done with an 8F chassis. Total wheelbase is 59'10" so it wouldnt quite fit a 60ft turntable but it could have a shorter tender instead. The cylinders are 18x22 so 8F's could be used too

 

https://www.flickr.com/photos/124446949@N06/51251501472/

 

[The Johnster]

The GW's aversion to trailing trucks was 'informed' by the South Devon banks. If you want a non-stop service to Plymouth, the engine has to be capable of fast running down to Newton Abbott, then to be able to haul the load over the lumpy bits without losing adhesion, and while Atlantics, Pacifics, and such have a tendency to lose their feet on steep banks because the trailing wheels relieve the driving wheels of some of their adhesion.  In the event, Britannia and Bullied light pacifics worked over the route without much fuss down to the wheel arrangement, though the Plymouth and Old Oak men didn't like the Brits. 

 

One of the jobs Brits had at Canton, where all the WR Brits ended up, was for the high mileage locos to be used on 'downline' work to Swansea and points west, which involves the savage exit from Neath on the down, 1 in 60 around a tight left hand curve straight off the platform standing start up to Skewen, and the locos managed this, so they couldn't have been all that hobbled by lightfootedness.  It was considered that the high mileage locos, with driving wheels worn down to nearer 6' diameter, were better than those fresh out of works, for this sort of thing. 

 

My childhood memories are of these locos and Castles, and it was very apparent that up trains leaving Cardiff General from platforms 1 or 2, a slight rise over the Canal Wharf bridge and a left hand curve before dropping down towards Newtown, were a very different experience with those two classes.  A Britannia would make a huge fuss of the job, slipping, picking up, slipping again, and the driver would be on a regulator knife edge between stalling and slipping, sanders spitting, and sometimes the following 'Marshfield Flyer' auto giving assistance in rear.  It would take two or three minutes for the train to clear the platform, and matters were not resolved until half of it was over the bridge.  This could be up to 16 bogies.

 

A Castle, on the other hand, when the guard gave right away, the driver would put her into forward gear, and open the regulator.   The loco would go chuff chuff chuff and pull the train out of the platform, the last coach would disappear around the corner of the Central Hotel, and that would be that.  Britannia, in preservation two years ago, managed without much fuss and no slipping at all with 11 bogies, and Tornado took 12 out of P3 in pouring rain with contemptuous ease.  So there was a difference in normal running, but it was coped with, and the GW were perhaps right to avoid pacifics, but not as right as they thought they were (nobody could be as right as the GW thought they were, which is why they got up everybody elses' noses so much!).

 

The attitude was that the Kings were enough to do the Plymouth jobs without a loco change at Newton Abbott, but of course assistance was available if they were overloaded.  But the Kings were of limited overall use due to their RA problems, and so were the 47xx.  So, the question is whether a 4-8-0 with 6'+ driving wheels capable of express work on the Churchward/de Glehn pattern would have been a better general express loco for all red routes than a Castle.  I would argue that it would have, but that it didn't because Swindon's innate sense of superiority and small c conservatism stated that Castles were good enough.  A 4-8-0 with a King boiler would have been sufficient, it doesn't need to be lengthened or fattened, but the rear drivers would have been well back under the cab.

 

These 8-coupled GW neverwazzas seem to appear cyclically on this thread, and someone (sometime it's me) always asks what they are for.  Big British steam suggestions will often tend to fall foul of this question because:-

 

a) the British loading gauge limits how big a loco can be before further expansion by lengthening the boiler becomes impracticable.

b) large driving wheels limit the expansion of the boiler downwards, admittedly ameliorated by the use of smaller driving wheels for express work from the 1940s.

c) the traffic does not demand a loco that needs to pull more than 15 bogies at high speed

d) in any case the length of trains is limited to 20 bogies tops by the capacity of loops, layby sidings, and signalling safety overlaps.  Very few main line stations had platforms that could accommodate more than 15 bogies, or room to expand their longest platforms without very major relaying, resignalling, and spending silly money.

e) any further expansion of the biggest locos would have probably neccessitad mechanical stoking or oil firing even if it had been possible.  Mechanical stoking would have been resisted by the companies because British coal is not suitable for it and the efficiency of it's burning would have been compromised, or so it seems to have been believed, and oil firing would not have been politically acceptable as the railway were expected to support the British coal industry, and the experiments that were carried out were only accepted because of a national coal shortage and considered a temporary measure.

[The Johnster]

23 minutes ago, sir douglas said:

Drawing of an unbuilt 4-8-2 class for Nigeria, at 12'6 tall including head lamp it would fit British loading gauge if modelled as SG and with 4'8" wheels it could be done with an 8F chassis. Total wheelbase is 59'10" so it wouldnt quite fit a 60ft turntable but it could have a shorter tender instead. The cylinders are 18x22 so 8F's could be used too

 

https://www.flickr.com/photos/124446949@N06/51251501472/

 

So it would not have been unlike a WD 2-10-0, or, I respectfully submit, capable of doing anything a 9F couldn't already do better and faster.  You can't make an express or even mixed traffic loco out of it because the larger driving wheels mean that the axles are higher up, which means the boiler has to be mounted higher up, and you run into loading gauge problems.  I agree that a shorter tender can be used in the UK because of the availability of water troughs.  Not sure why a loco with 4'8" driving wheels needs a 4-wheeled leading bogie, it 's never going to do more than about 50mph, and it might have been better as a 2-10-2.  Nice looker, though...

[AlfaZagato]

I'd imagine the bogie tender was for range, not so much for some aggressive hunger.   I don't know the operating climate in Nigeria with any detail, though.   Probably had longer uninterrupted runs with no chances to replenish fuel or water than is practice in the UK.  UK service could probably afford a three-axle tall tender.

 

In re my suggestion of a 4-8-0 King, @The Johnster, my suggestion was more to increase the King's viability for regular service.   Even taking the King down to Red availability increases her access twofold.   As @JimC mentions, just the basic math for another axle dividing the same weight down brings the King under by 125lbs/axle.   Admittedly, additional frame and another set of 6'6" drivers weighs more than 1500lbs.  So, also by his suggestion, reducing the wheelsize to something like 5'8" could maintain the desired performance, while keeping the total weight within the axleweight limit.