Imaginary Locomotives

[JimC]

Don't forget to consider firebox and ashpan versus axles when considering this. Doesn't the classic 0-4-4T have the box between drivers and bogie? I suppose one might go for 2-4-4T if wanting a longer boiler and outside cylinders as a development of an 0-4-4T if track were too tightly curved for a 2-6-2T. Might try a sketch. 

 

Faced with very heavy freight and passenger traffic on the tightly curved yet almost level Erewhon branch, Churchward very reluctantly told Holcroft to get him out a 2-4-4T based on the 3100s. Holcroft adapted the standard 4-6-0 bogie for the larger trailing wheels on the Prairie, altered the frames at the back, and apart from quite a lot of fiddling with brake rigging the job was done. Holcroft had wanted to alter the front end cosmetics according to some ideas he was mulling over, but Churchward insisted it was kept as standard as possible with the 31s.

 

In practice I reckon the weight distribution would be highly dubious with no chance of equalisation between trailing wheels and bogie, but hey, just a quick hack of the 2-6-2 drawing. The throwover at the back would be pretty spectacular too I reckon.

 

I've just looked at alternatives, a smaller boiler from the standard range or even something based on a Barry 0-4-4, but really keep coming up against better alternatives. Its far too away from my library of standard parts to consider sketching myself, but given a requirement for large coal and water capacity without the length getting out of control as the above does, would a wide firebox be something to consider? Gresley is much more the man for small classes than Churchward, might an GNR/LNER enthusiast consider a 3 cylinder 2-4-4T with a wide firebox, and maybe a booster unit on the bogie?

 

 

Edited June 11, 2022 by JimC

[rockershovel]

12 hours ago, JimC said:

Back tank on its own, not many. Water tank under the coal space - common.

The only loco I can think of with a back tank but no rear bunker, would be Dolgoch ... but that's a well tank with additional back tank... isn't it? 

[rockershovel]

12 hours ago, JimC said:

Back tank on its own, not many. Water tank under the coal space - common.

Same in US, I can't think of any US locos with back tank and coal in front 

 

I'd class the various geared types as tender locos 

Edited June 11, 2022 by rockershovel

[rodent279]

1 hour ago, JimC said:

Don't forget to consider firebox and ashpan versus axles when considering this. Doesn't the classic 0-4-4T have the box between drivers and bogie? I suppose one might go for 2-4-4T if wanting a longer boiler and outside cylinders as a development of an 0-4-4T if track were too tightly curved for a 2-6-2T. Might try a sketch. 

 

Faced with very heavy freight and passenger traffic on the tightly curved yet almost level Erewhon branch, Churchward very reluctantly told Holcroft to get him out a 2-4-4T based on the 3100s. Holcroft adapted the standard 4-6-0 bogie for the larger trailing wheels on the Prairie, altered the frames at the back, and apart from quite a lot of fiddling with brake rigging the job was done. Holcroft had wanted to alter the front end cosmetics according to some ideas he was mulling over, but Churchward insisted it was kept as standard as possible with the 31s.

 

In practice I reckon the weight distribution would be highly dubious with no chance of equalisation between trailing wheels and bogie, but hey, just a quick hack of the 2-6-2 drawing. The throwover at the back would be pretty spectacular too I reckon.

 

I've just looked at alternatives, a smaller boiler from the standard range or even something based on a Barry 0-4-4, but really keep coming up against better alternatives. Its far too away from my library of standard parts to consider sketching myself, but given a requirement for large coal and water capacity without the length getting out of control as the above does, would a wide firebox be something to consider? Gresley is much more the man for small classes than Churchward, might an GNR/LNER enthusiast consider a 3 cylinder 2-4-4T with a wide firebox, and maybe a booster unit on the bogie?

 

 

What about if you were to add an extra axle on to a 36xx radial tank, and extend the bunker?

[JimC]

13 minutes ago, rodent279 said:

What about if you were to add an extra axle on to a 36xx radial tank, and extend the bunker?

well, that works, if somewhat aesthetically challenged!

[Compound2632]

1 hour ago, JimC said:

Don't forget to consider firebox and ashpan versus axles when considering this. Doesn't the classic 0-4-4T have the box between drivers and bogie?

 

Exactly. That was the starting-point of my disquisition. Your fantasy Churchward / Holcroft 2-4-4T illustrates this: the starting-point is a conventional 0-4-4T. Once you move the cylinders from inside to outside, they have to sit further forward to clear the leading axle. What with the weight of a superheater as well, the engine becomes nose-heavy so needs an extra axle ahead of the cylinders to relieve the leading axle of the excessive weight. it's the same procedure that gives you the 43xx mogul from a conventional inside-cylinder 0-6-0 or the Prairie tank from an inside-cylinder 0-6-2T.

[rodent279]

27 minutes ago, JimC said:

well, that works, if somewhat aesthetically challenged!

Yes it does look a bit unbalanced!

[Miss Prism]

1 hour ago, JimC said:

 

Ah ha, a Big Birdcage! But does that coal v water ratio make sense?

 

[Compound2632]

Just now, Miss Prism said:

 

Ah ha, a Big Birdcage! But does that coal v water ratio make sense?

 

 But as with many tank engine classes, the bunker is part water tank.

 

I must say Jim's engine looks as if it would be happier with a leading bogie and bigger drivers - something like a Flower with a big bunker. 

[DenysW]

If one believes Trix (a company proud of being originally based in Bavaria, now part of Wurtemburg's Marklin empire) the Bavarian D XII does indeed have the leading axle in front of outside cylinders (probably on or close to Bern gauge by this time), then two driving axles, then a gap, then two axles under the cab. They don't model any of the Bavarian tanks I've seen from them (6 so far) with wide grates, tapered boilers, or Belpaire fireboxes. The compound express pacific S3/6 of 1908 is modelled with a wide grate, but not a Belpaire boiler.

 

Diff'rent folks, diff'rent strokes?

[JimC]

27 minutes ago, Compound2632 said:

 But as with many tank engine classes, the bunker is part water tank.

 

I must say Jim's engine looks as if it would be happier with a leading bogie and bigger drivers - something like a Flower with a big bunker. 

 

There was a MSWJR 4-4-4T given a GWR tapered boiler, but photos on line rather rare. 

 

http://www.gwr.org.uk/notes/mswjr10.jpg

[tythatguy1312]

52 minutes ago, Miss Prism said:

coal v water ratio make sense?

At that point you might want side bunkers instead of rear ones, as seen on multiple narrow gauge locomotives and the Italian GR 670 tender-tanks.


Speaking of this magnificently ugly thing, I'm honestly a little surprised a cab-forward of this layout wasn't tried for the UK, if nothing else than to see how it'd run. Could've had a niche as a parade piece/inspector's locomotive

Edited June 11, 2022 by tythatguy1312

[rockershovel]

1 hour ago, tythatguy1312 said:

At that point you might want side bunkers instead of rear ones, as seen on multiple narrow gauge locomotives and the Italian GR 670 tender-tanks.


Speaking of this magnificently ugly thing, I'm honestly a little surprised a cab-forward of this layout wasn't tried for the UK, if nothing else than to see how it'd run. Could've had a niche as a parade piece/inspector's locomotive

I can only assume that its purpose, like the American cab-forward types, was mitigation of crew conditions in long (Alpine?) Tunnels. 

 

It's an interesting question, because the UK did have at least one tunnel with severe problems of that sort and an established tradition of building one-off locos for particular problems.

 

But... a cab-forward bsnker would be of little use, because of fumes from the train locomotive. The only useful application would be a cab-forward loco which could handle the train single-handed, which was beyond the capacity of the most powerful steam loco ever to run in the UK and grossly over-powered for the rest of the route.

 

Gentlemen, the challenge is before you!

[eldomtom2]

4 hours ago, rockershovel said:

I can only assume that its purpose, like the American cab-forward types, was mitigation of crew conditions in long (Alpine?) Tunnels.

Maybe, but how many tunnels are there on the Milan-Venice route on which they were apparently used?

[John Besley]

18 hours ago, JimC said:

well, that works, if somewhat aesthetically challenged!

I'd hate to empty the Smokebox on that .... 

[Compound2632]

Atbara tank:

 

 

Bit of a crude lash-up, i'm afraid. It's unfortunate that the driving axle bearing springs have disappeared inside the side tanks...

 

But at least you can get at the smokebox.

[SteamedLyons]

There is of course the next logical step, to simply just update the 36xx as the 3631 class! Better aesthetics (?) and that's about it. I imagine cleaning out the smokebox on this would only be as bad as a 56xx in comparison to the above, though that's arguably marginal!

[The Johnster]

I can see a valid role for this 3631 class.  The obvious thing to do with it is to ditch the leading pony and make it into a 56xx, but that's already been done with the 56xx, and when I suggested here a while ago that the 56xx might have been developed into a South Wales Valleys passenger engine with 5'2" wheels, like a Swindon version of a Rhymney P in the same way as the 56xx is as Swindon version of a Rhymney R, it was pointed out that the pitch of the boiler would have had to have been higher in order for the smokebox to clear the cylinders, which would have been raised by 3.5 inches, which may have affected the loco's stabiliy even at the 50mph which was the line speed for the greatest part of the Valleys network.  3631 gets around that problem and is probably able to negotiate tighter curves than a 56xx as well, and the larger driving wheels (I'm assuming these are 5'2") would negate the loss of water capacity in the tanks caused by the larger splasher recesses in the bottoms of them.

 

The adhesive weight is well distributed over the driving wheels and I would expect the locos to have been able to haul 5-coach loads to the same timings as the 56xx in the Valleys, releasing 56xx for the colliery trips that the were arguably more suited to.  Given the success and longevity of similar 2-4-2Ts on the LNW and L&Y in the hilly hinterlands of Manchester and Leeds, 3631 sounds like a viable Valleys passenger loco to me!

 

The argument against it is what actually happened, the availability of constituent/absorbed 0-6-2Ts in this role, especially the TVR A and Rhymney P classes, both of which were rebuilt with GW boilers and components and which were good enough to last until the arrival of the 94xx, which was amongst other things intended to replace these constituent/absorbed locos.  94xx certainly saw their share of passenger work in the Valleys, the Machen-New Tredegar services being one of their stamping grounds, and Tondu's allocation of 94xx were used exclusively on passenger work for some reason.

[Flying Pig]

On 11/06/2022 at 17:47, rockershovel said:

I can only assume that its purpose, like the American cab-forward types, was mitigation of crew conditions in long (Alpine?) Tunnels. 

 

More info at the link.  They were basically a wide firebox 4-6-0, made possible by reversing the boiler on the frames - all else followed from that.

 

https://www.reddit.com/r/trains/comments/giflsb/the_fs_class_670007_a_unique_cabforward_steam/

 

[Compound2632]

5 hours ago, Flying Pig said:

More info at the link.  They were basically a wide firebox 4-6-0, made possible by reversing the boiler on the frames - all else followed from that.

 

Looks more like a straightforward 0-6-4 to me, with the qualification that the water is carried in a tender at the front and it is usually run in reverse! 

[The Johnster]

Hmm. 
 

Well, Whyte notation is not perfect; it is certainly defeated by some C19th French esoterica!  Is the ‘front’ of this loco where the cab is situated or where the engine, the cylinder block is situated?  To my mind it’s a 4-6-0 cab-forward, clearly intended to be driven in that direction in service, but if you hold that the engine is at the front, it’s an 0-6-4, and you are no more/just as likely to be correct than me AFAICS.  It’s probably not a situation that Whyte considered.  Somebody more knowledgeable might be able to to clear up my confusion…

 

A clear and uncomplicated method of delineating locomotive wheel arrangements has so far eluded the wit of man.  The most comprehensive seems to be the UIC, but it’s massively complex and dense (to be fair it has to be to cover all the bases!).  I tend to think in terms of Whyte for framed locos and Bo-Bo, C-C, etc for locos with bogies; I think of the Ffestiniog’s double Fairlies as B-Bs, but can’t manage to visualise Malletts or Garratts in that way.  I s’pose it’s just what I’m used to!

[DavidB-AU]

14 hours ago, The Johnster said:

Well, Whyte notation is not perfect; it is certainly defeated by some C19th French esoterica!  Is the ‘front’ of this loco where the cab is situated or where the engine, the cylinder block is situated?  To my mind it’s a 4-6-0 cab-forward, clearly intended to be driven in that direction in service, but if you hold that the engine is at the front, it’s an 0-6-4, and you are no more/just as likely to be correct than me AFAICS.  It’s probably not a situation that Whyte considered.  Somebody more knowledgeable might be able to to clear up my confusion…

 

A Forney is often listed as a 0-4-4T, but Matthias Forney himself insisted they were supposed to run bunker first so should be a 4-4-0T.

 

Cheers

David

[Budgie]

On 20/06/2022 at 16:47, The Johnster said:

Is the ‘front’ of this loco where the cab is situated or where the engine, the cylinder block is situated?

 

Do what the North Americans do with their diesels. Paint a capital F on the frame of the locomotive, and by definition that is the front. 

[john new]

On 11/06/2022 at 17:47, rockershovel said:

I can only assume that its purpose, like the American cab-forward types, was mitigation of crew conditions in long (Alpine?) Tunnels. 

 

It's an interesting question, because the UK did have at least one tunnel with severe problems of that sort and an established tradition of building one-off locos for particular problems.

 

But... a cab-forward bsnker would be of little use, because of fumes from the train locomotive. The only useful application would be a cab-forward loco which could handle the train single-handed, which was beyond the capacity of the most powerful steam loco ever to run in the UK and grossly over-powered for the rest of the route.

 

Gentlemen, the challenge is before you!

As it was then, the obvious answer to problematic steam working is electrification. IIRC the St Clare tunnel in the USA an early example, Raven’s ideas on the NER, the tube network (albeit fumes there rather than haulage issues) and before WW2 delayed it the LNER’s answer to Worsbrough Bank and then onwards via Woodhead was 1500v electrification. Slightly tongue in cheek but the steam engine era was the odd intrusion between the horse and electrification, surprisingly long lived given how early in date pioneer electrics were being trialled.

 

Edited June 22, 2022 by john new

[Compound2632]

16 minutes ago, john new said:

As it was then, the obvious answer to problematic steam working is electrification. IIRC the St Clare tunnel in the USA an early example, Raven’s ideas on the NER, 

 

The NER scheme was only one of several that were killed off by the Great War. The Midland's Lancaster-Heysham-Morecambe experiment was intended to pave the way for a derby - Manchester scheme; I believe the LNWR was looking at Crewe - Carlisle. Then of course both the LB&SC and LSWR schemes south of the river, which were implemented.