Imaginary Locomotives

[Niels]

On 06/07/2019 at 00:19, Corbs said:

Mucking around with some drawings wondering how one might make a UK version of a Chapelon loco, taking the 240A/240P as inspiration.

Top one is a Chapelon 240A rebuild of the pacifics.

2nd from top is Tuplin examining how a simple expansion 4 cylinder 4-8-0 could be made in the UK loading gauge

3rd is Tuplin's drawing overlaid on a King (centre driver of King is on the 2nd driving wheel of the 4-8-0)

4th is a King for reference

 

Chapelon was able to make use of narrow fireboxes on the 240 designs (I assume these were not mechanically stoked?), I chose the King as a comparison because of this and also the driving wheel diameter.

The King's driving wheels are 6 ft 6 in (1981mm), the 240A's are 6ft 2.8in (1900mm), so not a great difference.*

Tuplin's 4-8-0 is shorter than the King, which makes sense as the main line ones these days have cut down boiler fittings etc. to fit on the modern railway/non GWR lines, but Tuplin has used all the available space as evidenced by the stubby dome and chimney.

 

It's odd how Tuplin seems to have drawn the loco with 4 x 20" diameter cylinders abreast of each other rather than 2 pairs of larger cylinders offset from one another like the King, Princess etc.

 

*although listed as 6ft 0in on the drawing, not sure why.

 

I wonder, if one were so inclined, that a 'Princess' boiler could be used, with the wide firebox cut off and substituted for a narrow one, the smokebox extended. Using a P2 chassis for four 6ft 2in driving wheels, closely spaced, rear of chassis removed and front adapted to take a bogie.

Chapelon had the LP cylinders inside and the HP ones outside on the 240A/240P, and the HP cylinders were only marginally bigger than a 'King's, so a slight size reduction could be made.

 

 

Edited July 7, 2019 by Niels

[Traintresta]

4 hours ago, RLBH said:

Found a reference:

 

http://www.steamindex.com/people/coleman.htm

 

Cox's Chronicles of Steam is the source, it was a March 1942 suggestion by Coleman to Stanier of 12 possible postwar standard locomotives, also including a 2-8-4T based on the 8F, and an LMS version of the GWR 56xx 0-6-2T. Apparently all worked up in sufficient detail to allow production design to commence if authorised.

A 2-8-4t would have been a bit beastly. The 0-6-2t sounds intriguing, Fowler proposed one before but the result was the 3p 2-6-2t. 

[Niels]

Further to the UK 4-8-0

If The outside 17 inch high-pressure cylinders were put forward between boggie wheels it should have been possible to be UK loading gauge legal.

The efficiency of a very good fourcylinder compound versus a very good two-cylinder simple was measured in Germany 1941.

A Norwegian Compound 2-8-4 with 1550mm wheels were pitted against a two cylinder simple 01 Pacific with 2000mm wheels and won.

It is somehow described here in german.

 

Norwegian 2-8-4 versus German Pacific.

 

I will try and plot the Norwegian against the 01.

 

Steam consumption

 

 

Three cylindered simples used 6% more and four cylindered around 10% more than twins for same job.

Edited July 7, 2019 by Niels

[melmerby]

22 hours ago, PenrithBeacon said:

The consensus view in the late forties was that the rebuilt Scot was the best, the most powerful, 4-6-0 in the country until the King's were rebuilt with double chimneys in the fifties

I read that the Kings also benefited from better optical kit to set the motion up during the BR period, so were always "Cock-on" when ex-works, whereas only sometimes during the GWR period.

[melmerby]

1 hour ago, Niels said:

Further to the UK 4-8-0

If The outside 17 inch high-pressure cylinders were put forward between boggie wheels it should have been possible to be UK loading gauge legal.

 

Plenty of UK locos with more than 17" cylinders outside

The LMS compound's LP cylinders, which were outside, were 21" x 26"

[melmerby]

On 06/07/2019 at 18:47, The Johnster said:

  I doubt there was much between them in practice, although the Scot's larger driving wheels possibly gave it an edge in speed.

IIRC no Scot was officially timed over 100mph, Kings (& Castles) were.

The ton up club is quite exclusive with (AFAIK) only the MN, both Stanier pacifics and both Gresley pacifics (A3/A4) & Peppercorn's A1 also up there.

[Niels]

26 minutes ago, melmerby said:

Plenty of UK locos with more than 17" cylinders outside

The LMS compound's LP cylinders, which were outside, were 21" x 26"

 

If the connecting rods attack second or third driver it is not possible to  have cylinders closer than 6 feet 8 and a half inch apart as conrods must be outside coupling rods.

UK loading gauge many places  did allow 8 feet 8 and a half inch at platform level and this left 24 inches for outside of cylinders.

Flanges took 4 inches so cylinders over 20 inch was not very common.

If conrods worked first driver inside of coupling rods it was possible to have 6 feet 3 cylinder distance and thus something like22-23 inch cylinders on straigth track.

 

Edited July 7, 2019 by Niels

[scots region]

This is an idea for a kind of 'dream layout' that I've come up with recently: a Calais to Dover Bridge is constructed in the later part of the nineteenth century. Would this lead to a stronger continental influence over British designs or would there be no overall change? 

Edited July 7, 2019 by scots region

[Niels]

4 minutes ago, scots region said:

So an idea for a kind of 'dream layout' that I've come up with recently is a Calais to Dover Bridge being constructed in the later part of the nineteenth century. Would this lead to a stronger continental influence over British designs or would there be no overall change? 

 

To pay for the construction of the bridge it would be nessecary to allow running continental loading gauge waggons in UK.

It could maybe have been done before WW1 where railways  paid dividends.

Not after where lorries took over.

[scots region]

1 minute ago, Niels said:

 

To pay for the construction of the bridge it would be nessecary to allow running continental loading gauge waggons in UK.

It could maybe have been done before WW1 where railways  paid dividends.

Not after where lorries took over.

 

Thats why I felt that the 1880s-90s would be the best time for a project of this scale, before economic and security concerns made it impractical. Although a bridge straight across the channel would probably change things enough to prevent or alter WW1 all together. 

[Niels]

1 minute ago, scots region said:

 

Thats why I felt that the 1880s-90s would be the best time for a project of this scale, before economic and security concerns made it impractical. Although a bridge straight across the channel would probably change things enough to prevent or alter WW1 all together. 

 

 

 

A bridge/tunnel were part of  vision behind the GC London extension.

 

Instead  Europe became part of   USAs empire.

[brack]

I'm imagining something like an enormous solway viaduct. That'd play hell with shipping.

 

[rockershovel]

1 hour ago, brack said:

I'm imagining something like an enormous solway viaduct. That'd play hell with shipping.

 

 

It all seems very faux-Victorian, what do they call it, steam punk? I’d envisage a sort of super-Forth Bridge with a bascule section, or possibly a tunnelled centre section from artificial islands with Gothic castellated portals? 

 

[rockershovel]

1 hour ago, scots region said:

 

Thats why I felt that the 1880s-90s would be the best time for a project of this scale, before economic and security concerns made it impractical. Although a bridge straight across the channel would probably change things enough to prevent or alter WW1 all together. 

 

Alternate history is an endless source of such things, but I rather doubt that. The period 1873-1896 was a time of financial depression, particularly in the U.K. Germany began a long process of wars of expansion and unification in the 1860s, and the United States sucked in huge sums of foreign capital for its own projects - most notably, the building of a Trans-Continental railway and the industrialisation which followed.

 

As to preventing WW1, I also doubt that. Relations between Britain, France and Germany have long been strained by their similar, conflicting interests. Britain and France came very close to war in 1912, and Germany fully expected the BEF to make a gesture and then retreat in 1914 - indeed, the French also thought this likely. There was little political support for alliance with France, and if the Germans had (as they fully expected) repeated their smashing victory of 1870 without engaging the BEF, then the British would have had few options but to negotiate a settlement. 

 

I don't see how a Trans-Channel Link would have materially affected that, least of all a Bridge - which can be easily blown and subsequently rebuilt (a Tunnel is a much more difficult proposition in that respect)

 

 

 

[john new]

My memory is that the Victorian channel tunnel project was started and a mile or two was dug circa 1870. Can't recall now whether it failed due to lack of capital or media pressure/interference from sources fearing invasion.

[melmerby]

54 minutes ago, john new said:

My memory is that the Victorian channel tunnel project was started and a mile or two was dug circa 1870. Can't recall now whether it failed due to lack of capital or media pressure/interference from sources fearing invasion.

Part of Sir Edward Watkin's grand scheme of things to join railways in which he had an interest together (Great Central, South Eastern & Nord) to make a through route from Manchester to Paris

It was started 1880ish but blocked by Parliament on security grounds after about 2000 yards had been dug.

[Gibbo675]

4 hours ago, melmerby said:

IIRC no Scot was officially timed over 100mph, Kings (& Castles) were.

The ton up club is quite exclusive with (AFAIK) only the MN, both Stanier pacifics and both Gresley pacifics (A3/A4) & Peppercorn's A1 also up there.

Hi Kieth,

 

I have ridden upon the footplate of 45407 at 96 mph and 76079 at 89 mph, what has "officially"  got to do do with anything in reality ?

 

Both locomotives being mixed traffic 45407 being balanced for goods work and 76079 with 5'3" wheels.

 

That a Scot should not manage ton up is preposterous.

 

Gibbo.

[melmerby]

6 minutes ago, Gibbo675 said:

 

That a Scot should not manage ton up is preposterous.

 

Gibbo.

Not if it was never tried.

It should be well capable, that doesn't mean it did.

A Coronation should be able to beat Mallard but was never tried in similar circumstances.

There are plenty of claims of "super" speeds for locos but not many have been officially (or even unofficially) properly timed.

If a "Scot" had done over a ton someone would have claimed it.

 

[DavidB-AU]

3 hours ago, john new said:

My memory is that the Victorian channel tunnel project was started and a mile or two was dug circa 1870. Can't recall now whether it failed due to lack of capital or media pressure/interference from sources fearing invasion.

 

The latter. This is typical of the Dorothy Dixers being asked at the time.

 

Cheers
David

[34theletterbetweenB&D]

On ‎06‎/‎07‎/‎2019 at 18:47, The Johnster said:

... Scot and King, and it seemed to me that both classes were overpowered in their final forms for the frames.

A major gripe of Chapelon was that the power potential of steam in Europe was limited by the failure to progess in permitting higher axleloads by laying larger section rail. (He looked with envy at North American practise where axleloads exceeding 30 tons were emerging in the late 1930s, and that wasn't the limit yet.)

 

In Europe frames suffered as power development in boiler and cylinder outputs  improved, but without any ability to put proportionally more metal into the frame. Superior design went some way to obtaining more strength and fatigue resistance, but frames broke because they were daily taken beyond the load they could bear. Every bit of cylinder output goes to work on the frame between cylinder and big end...

 

Over in North America steel cast frames with integral cylinders could be provided. This meant just two LARGE cylinders could wallop out power outputs of Chapelon's dreams, and be confidently expected to go on 'forever' without structure failure.

 

This in my opinion was the critical shortcoming of the 5AT project. Yes, it is clearly possible to produce yet more power from the 4-6-0 format: but will the frames and motion stand the increased beating? Not without moving away from mild steel to something much more expensive. A largely titanium structure steam loco, now that would be exciting...
 

 

On ‎06‎/‎07‎/‎2019 at 19:00, Corbs said:

I agree, but isn't it odd that you can see that, and so can I, but Tuplin apparently can't? Unless we have access to much more data than he did, it seems strange to sketch out such a loco...

Perhaps some sort of parallel to our wishlisting models: in his case without regard to all the requirements to achieve the power output, in ours without a full insight into the commercial reality of the business? 

 

Tuplin had sufficient technical information to know this, I rather feel his attitude was to show that the 'exciting' 40% uplift in tractive effort on the basis of cylinder volume and boiler pressure was possible, and let someone else figure out the details of securing sufficient continuous boiler output to fully exploit it. (One way, don't use coal but oil. That eliminates the ash problem and means the fireman won't keel over when his driver attempts maintaining 70mph up a South Devon bank, and much increased boiler pressure - Tuplin thought circa 180 psi was always sufficient, despite evidence against - and install the largest feasible superheater. This last the A4's 'secret' in addition to the Kylchap ejector, easily the largest superheater ratio  of any UK pacific accessible to Tuplin, he actually documents it!)

 

19 hours ago, Traintresta said:

A 2-8-4t would have been a bit beastly...

 Handsome actually. The Stanier 2-6-4T model's body shell very easily takes the Stanier 8F mechanism, replacing the original '2-6' element, and an entirely credible looking machine emerges. Seen at least two kit built examples running at exhibitions, and didn't hear a single adverse comment on either occasion. It simply looks so 'right'.

[RLBH]

7 minutes ago, 34theletterbetweenB&D said:

 Handsome actually. The Stanier 2-6-4T model's body shell very easily takes the Stanier 8F mechanism, replacing the original '2-6' element, and an entirely credible looking machine emerges. Seen at least two kit built examples running at exhibitions, and didn't hear a single adverse comment on either occasion. It simply looks so 'right'.

Which I think is why it keeps coming up. The work existed, it was technically fairly straightforward, and it looks right.

[34theletterbetweenB&D]

The real problem of the Stanier 2-8-4T is an operating slot. What would it have been uniquely suitable for? It appears that all the LMS 2-6-4T were good at even the sloggiest tasks such as banking up Shap and Beattock, and were also good for bowling along well into the 80s with full size class 4 passenger loads. They really were all-rounders in highest degree.

[The Johnster]

14 hours ago, melmerby said:

Not if it was never tried.

It should be well capable, that doesn't mean it did.

A Coronation should be able to beat Mallard but was never tried in similar circumstances.

There are plenty of claims of "super" speeds for locos but not many have been officially (or even unofficially) properly timed.

If a "Scot" had done over a ton someone would have claimed it.

 

It very probably was, and exceeded.  Had City of Truro achieved whatever it was that it actually, it did without an inspector on the footplate and a railway journalist with a stopwatch, would anyone have taken any notice of the Postal Inspector's timings?  And this was, and still is, disputed because it wan't official.  A timing of 140mph (!) based on signalbox passing times and timed on the footplate by some people who would not be described as amateurs including Collett and IIRC Stanier, was made for 2904 Lady of Lyon on a running in turn on the Badminton cut-off 2 years later, but the circumstances were such that those involved did not particularly want to draw attention to themselves and had in fact very nearly got themselves all killed.  It was apparently done for a bet that a new loco could achieve more than 100mph running light.  The actual speed is not known, but they were going very fast indeed and had trouble pulling up for the junction at Wooton Bassett.

 

A lot of very fast running went unrecorded by drivers who regarded it as all in a day's work.  Many steam loco did not have speedometers, and those that did would not have had them properly calibrated, especially as they took the speed from the wheel rotation which increases as the tyres wear without actually increasing the speed of the loco.  Speed was mostly estimated from passing times, and it was more important to maintain schedule than worry about how fast you were going, and average speeds were what were referred to rather than temporary peaks at the bottom of banks

[RedGemAlchemist]

2 hours ago, 34theletterbetweenB&D said:

The real problem of the Stanier 2-8-4T is an operating slot. What would it have been uniquely suitable for? 

Considering some of the demented designs railways have created over the years I feel "to see if they could" as being a perfectly reasonable and realistic explanation. Alteratively, extremely heavy goods like moving continents or trying to desperately create something so Riddles' 9F wasn't used instead (not that I have a problem with the 9F.) 

Edited July 8, 2019 by RedGemAlchemist

[rodent279]

On 06/07/2019 at 19:08, The Johnster said:

It sounds a bit of a stretch to say a class 5 loco was better than a class 7, and you've correctly pointed out that the real comparison is between a Black 5 and a Hall, but poor coal could very easily reduce the performance of a Swindon firebox designed for best Welsh, and the Black 5's was designed to burn ordinary Yorkshire; this is probably enough to level the playing field.  I remember speaking to Hereford old timers who reckoned that a Saint was better than a Castle for the North to West main line work they had to cope mostly with, a 2 cylinder loco with Stephenson valve gear and a long piston stroke being very useful on those long slog climbs.

I suppose the County 4-6-0 was intended to provide the boiler power of a Castle with the punch and hill climbing abilities of the Saints/Halls.