Imaginary Locomotives

[brack]

5 hours ago, rockershovel said:

 

Oh, you can’t leave it at that! Do tell! 

Drawings in either the old or new sand hutton railway books. Greenly proposed it, the power bogie being 2-8 pivoted quite far forward, the trailing bogie under cab/bunker.

[Corbs]

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 6, 2019 by Corbs

[rodent279]

16 hours ago, The Johnster said:

I think the main point about the GWR Hawksworth/Mattingley pacific is that it was so much talked about, but never even seriously considered for building.  A pacific had been tried before on the GW, and not been worth pursuing, and in the late 40s Castles were capable of most of the work, though I am sure the loco dept would have liked more King sized locos for the heaviest work.  They were of course hobbled by the Civil Engineer, who didn't like the axle loads.  A King is about the biggest you can get a 4-6-0 to go without sacrificing wheel diameter to the extent that you curtail top speed and ride within the loading gauge.  

 

It's close to what the basic layout will sustain as well; note that when power output was increased by double chimneys and other tweaks in the 50s the locos dropped like ninepins after a few years with broken frames, something that also happened to the similarly uprated rebuilt Royal Scots.

 

When a pacific was sent to the WR, it was not liked (except at Canton, where a big free-steaming boiler and the capacity of a 2 cylinder loco to slog was appreciated on the long drag from the bottom of the Severn Tunnel to Badminton with 14 on unassisted) and in any case intended only to perform Castle work, not King.  By and large, GW men saw them as pointless.  For the reasons stated by others; shorter distance runs and Welsh coal.

 

A Hawksworth/Mattingley pacific would most likely have been a Swindon version of the Princess Royal, a rather dated design in the late 1940s.  This would have been long enough to demand oval buffers and too long for King sized turntables.

The last point is a good one. Did the GWR have any turntables suitable for a Pacific?

[Compound2632]

52 minutes ago, rodent279 said:

The last point is a good one. Did the GWR have any turntables suitable for a Pacific?

 

Infrastructure limitations such as this are often overlooked in dreaming up these fantasy locomotives. The Great Northern Railway had nothing bigger than a 4-4-0 right down to the end, because the workshop at Dundalk works could handle nothing longer. Needless to say, the Great Northern got very good at 4-4-0s!

[34theletterbetweenB&D]

12 hours ago, Corbs said:

...Chapelon was able to make use of narrow fireboxes on the 240 designs (I assume these were not mechanically stoked?)...

...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.

 

...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...

Chapelon preferred a long (narrow) firebox if he could get sufficient grate area for the required power output, gives his reasoning in 'La Locomotive a Vapeur'. Now that does require great care in firing. What he had on his side in this respect was French operational practise. Firstly before you got to go on the footplate of a large French loco you were academically trained and required to pass an examination, both Drivers and Firemen. The crew knew the theory behind the loco's design, that the power output was only attainable if the loco was operated correctly: specifically the use of compounding and resuperheat which required extremely careful driving and firing to deliver a fuel efficiency much superior to anything achieved by UK steam design.

 

Chapelon was the presiding genius of steam, Tuplin wasn't! He obtains the 56.000lb of theoretical tractive effort without the steam economies of compounding and higher boiler pressure. For any given power output his design requires roughly twice the volume of steam the Chapelon design needs. When pushed to the limit it won't be able to burn coal fast enough to maintain boiler pressure, and against an achieveable  sustained power demand it will fill the ashpans at twice the rate of the Chapelon compound.

[The Johnster]

7 hours ago, rodent279 said:

The last point is a good one. Did the GWR have any turntables suitable for a Pacific?

Depends on the actual Pacific.  Britannias and 9Fs were no problem at most GW sheds, and neither were Gresley A1s and A4s during the exchanges; A4s are commendably compact machines for the power they can put down!  LMS pacifics were a lot longer than any of these classes, and were presumably not used on the Midland section for this reason, although the Midland’s legacy of shorter, lighter, more frequent services may have been a factor in this.  By Nationalisation, the 8P rebuilt Scots were available in increasing numbers.  Midland services changed locos at Leeds if they were going beyond that, so one might argue that they were similar to the GW’s in being to ‘get away’ with 4-6-0s. 

 

 

[Flying Pig]

45 minutes ago, The Johnster said:

By Nationalisation, the 8P rebuilt Scots were available in increasing numbers.  

 

Rebuilt Scots were 6P at nationalisation, later raised to 7P.

[The Johnster]

Always thought they were 8P, comparable to Kings and Lord Nelsons. 

[PenrithBeacon]

On 05/07/2019 at 14:25, Traintresta said:

From what I understand the LMS 2-6-2 would have been very much like the V2 in respect of its relationship to the Pacific’s. The resin it probably wasn’t built was that there wasn’t much need to have a loco in between the black 5 and the Pacific’s. The LNER didn’t have a decent, all-around 4-6-0 at that point. 

An LMS 2-6-2 is news to me it, wasn't shown on the diagrams of proposed LMS standard engines during the Stanier regime.

The proposed engines that weren't built were the class 3 0-6-2T, Class 4 4-6-0 and the Class 8 2-8-4T.

Regards

[Traintresta]

31 minutes ago, PenrithBeacon said:

An LMS 2-6-2 is news to me it, wasn't shown on the diagrams of proposed LMS standard engines during the Stanier regime.

The proposed engines that weren't built were the class 3 0-6-2T, Class 4 4-6-0 and the Class 8 2-8-4T.

Regards

It’s in the book locomotives that never were. 

[PenrithBeacon]

3 minutes ago, Traintresta said:

It’s in the book locomotives that never were. 

Locomotives That Never Were https://www.amazon.co.uk/dp/0710603266/ref=cm_sw_r_cp_apa_i_JbniDbW5K2BTF

I gather that this is the book. 

[Flying Pig]

53 minutes ago, The Johnster said:

Always thought they were 8P, comparable to Kings and Lord Nelsons. 

 

So did they

Edited July 6, 2019 by Flying Pig

[Gibbo675]

1 hour ago, The Johnster said:

Always thought they were 8P, comparable to Kings and Lord Nelsons. 

Hi Johnster,

 

I knew an ex Springs Branch driver and he used to say a good Scot was better than an average Big Lizzy. He also mentioned that when going fast they would get into a rolling motion that was quite unnerving at times.

 

Gibbo.

[Traintresta]

28 minutes ago, PenrithBeacon said:

Locomotives That Never Were https://www.amazon.co.uk/dp/0710603266/ref=cm_sw_r_cp_apa_i_JbniDbW5K2BTF

I gather that this is the book. 

Yes, and the price is not bad either, it was £35 a few weeks back but I picked up a copy on eBay for £15. 

[PenrithBeacon]

1 minute ago, Traintresta said:

Yes, and the price is not bad either, it was £35 a few weeks back but I picked up a copy on eBay for £15. 

Is a date quoted for this proposal? About ten years ago I read through all the LMS Loco Committee minutes for 1930-40 and I don't recollect any mention of a 2-6-2.

[Traintresta]

7 minutes ago, PenrithBeacon said:

Is a date quoted for this proposal? About ten years ago I read through all the LMS Loco Committee minutes for 1930-40 and I don't recollect any mention of a 2-6-2.

It was a wartime considerationfor a post war mixed traffic loco but it apparently didn't go very far.

[The Johnster]

30 minutes ago, Gibbo675 said:

Hi Johnster,

 

I knew an ex Springs Branch driver and he used to say a good Scot was better than an average Big Lizzy. He also mentioned that when going fast they would get into a rolling motion that was quite unnerving at times.

 

Gibbo.

We had a goods guard in my link at Canton who'd been a fireman at Patricroft in the early 60s, who'd have agreed with these sentiments, and I've heard more than a few accounts of them being a bit rough to ride on.  I got the impression that mileage since the last works visit was a very significant factor.  He'd get into 'free and frank discussions' with our old hand drivers over the relative merits of Scot and King, and it seemed to me that both classes were overpowered in their final forms for the frames.  I doubt there was much between them in practice, although the Scot's larger driving wheels possibly gave it an edge in speed.

 

That an original form Castle was better than a parallel boilered Scot is a proven theory, but my impression of rebuilt Scots, admittedly hearsay as I've no experience of them, is that they'd have run rings around a Castle in any form.  Until they cracked their frames.

[Gibbo675]

6 minutes ago, The Johnster said:

We had a goods guard in my link at Canton who'd been a fireman at Patricroft in the early 60s, who'd have agreed with these sentiments, and I've heard more than a few accounts of them being a bit rough to ride on.  I got the impression that mileage since the last works visit was a very significant factor.  He'd get into 'free and frank discussions' with our old hand drivers over the relative merits of Scot and King, and it seemed to me that both classes were overpowered in their final forms for the frames.  I doubt there was much between them in practice, although the Scot's larger driving wheels possibly gave it an edge in speed.

 

That an original form Castle was better than a parallel boilered Scot is a proven theory, but my impression of rebuilt Scots, admittedly hearsay as I've no experience of them, is that they'd have run rings around a Castle in any form.  Until they cracked their frames.

Hi Johnster,

 

I have it on good authority from a Western men who also happens to be Welsh that said he preferred a Black five to a Castle if the coal was bad !

Mind you, a black five is just a doubly improved Hall with the wobbly bits on the outside.

 

Gibbo.

[Corbs]

6 hours ago, 34theletterbetweenB&D said:

 

Chapelon was the presiding genius of steam, Tuplin wasn't! He obtains the 56.000lb of theoretical tractive effort without the steam economies of compounding and higher boiler pressure. For any given power output his design requires roughly twice the volume of steam the Chapelon design needs. When pushed to the limit it won't be able to burn coal fast enough to maintain boiler pressure, and against an achieveable  sustained power demand it will fill the ashpans at twice the rate of the Chapelon compound.

 

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.

 

 

EDIT: also, looking at relative sizes, the 240P is only about 20cm taller than a 'full fat' King (as opposed to 'semi skimmed')

King: 13 ft 4 3⁄4 in (4.083 m)

240P: 14 ft 0.15 in (4.271 m )

Edited July 6, 2019 by Corbs

[The Johnster]

5 minutes ago, Gibbo675 said:

Hi Johnster,

 

I have it on good authority from a Western men who also happens to be Welsh that said he preferred a Black five to a Castle if the coal was bad !

Mind you, a black five is just a doubly improved Hall with the wobbly bits on the outside.

 

Gibbo.

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.

[PenrithBeacon]

1 hour ago, The Johnster said:

We had a goods guard in my link at Canton who'd been a fireman at Patricroft in the early 60s, who'd have agreed with these sentiments, and I've heard more than a few accounts of them being a bit rough to ride on.  I got the impression that mileage since the last works visit was a very significant factor.  He'd get into 'free and frank discussions' with our old hand drivers over the relative merits of Scot and King, and it seemed to me that both classes were overpowered in their final forms for the frames.  I doubt there was much between them in practice, although the Scot's larger driving wheels possibly gave it an edge in speed.

 

That an original form Castle was better than a parallel boilered Scot is a proven theory, but my impression of rebuilt Scots, admittedly hearsay as I've no experience of them, is that they'd have run rings around a Castle in any form.  Until they cracked their frames.

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

Edited July 6, 2019 by PenrithBeacon
Three more words

[rodent279]

13 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

Does make me wonder what a Lord Nelson could have done with a similar rebuild.

[RLBH]

17 hours ago, Traintresta said:

It was a wartime considerationfor a post war mixed traffic loco but it apparently didn't go very far.

A Tom Coleman design, apparently, possibly of similar vintage to the 4-6-4 and 4-8-4 proposals.

[Traintresta]

Just now, RLBH said:

A Tom Coleman design, apparently, possibly of similar vintage to the 4-6-4 and 4-8-4 proposals.

Yes that’s correct. Hence it never reached the board. 

[RLBH]

2 minutes ago, Traintresta said:

Yes that’s correct. Hence it never reached the board. 

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.