Imaginary Locomotives

[Corbs]

I doubt it, the boiler proposed for the Crosti 5 would have been unique to that class I think

92220 did the model that inspired my photoshop (though theirs is more accurate)

 

 

[Northmoor]

19 hours ago, Corbs said:

Wanted to set myself a challenge of creating the rumoured Crosti/Caprotti Standard 5, using only images from Wikimedia Commons, on one cup of tea.

 

Congratulations Corbs, that is without question the ugliest locomotive anyone has created so far on this thread.  I'm going off to look at some photos of highly-polished Big Four locomotives, hoping it will settle my stomach.

[westerner]

Nothing wrong with big and ugly locos.

[richard i]

The crosti boiler standard five would have same boiler as a normal one, but taper at the bottom rather than top. I thought I could just adapt a standard five body, but it is a bit more work than that. It does make into a great model. I used a Bachmann chassis and a djh top with crosti bits from djh . Maybe horsy spares might provide the missing bits these days too. 

 

[Corbs]

That makes sense, presumably having the taper at the bottom allows room for the preheater underneath?

 

This is mostly an old pic but I updated it slightly as some bits were bugging me, added the streamlined 4-6-4 and converted the blue one to have an Ivatt cab and front end.

1 - Stanier's Princess Coronation
2 - Ivatt's final iteration of the 4-6-2
3 - 'What if Ivatt used the Coronation boiler with a 2 cylinder layout and 4 smaller driving wheels for fast freight?'
4 - Streamlined 4-6-4 - this was described by E.S. Cox along with a basic drawing, the idea was to compete with internal air travel. Princess Royal-sized wheels to allow the largest boiler possible, large firebox with mechanical stoker, roller bearings, large tender, streamlining retained
5 - Almost a de-streamlined version of the above
6 - 'What if we took the large boiler, firebox, mechanical stoker etc and put it on the 2-cylinder chassis?'

 

I used to have the 2-10-4s etc at the bottom but they were so ludicrous they annoyed me, whereas I quite like the proportions of these ones.

 

[rockershovel]

I can’t quite find the designs with the trailing bogie credible - apart from anything else, the tenders look too small? Austerity, LNER and BR experience seems to demonstrate that the 2-8-2 and 2-10-0 represent the limit of usable size for U.K. conditions, with the 2-8-0 the biggest type for most practical uses in the pre-nationalisation era. 

[rodent279]

5 hours ago, rockershovel said:

I can’t quite find the designs with the trailing bogie credible - apart from anything else, the tenders look too small? Austerity, LNER and BR experience seems to demonstrate that the 2-8-2 and 2-10-0 represent the limit of usable size for U.K. conditions, with the 2-8-0 the biggest type for most practical uses in the pre-nationalisation era. 

Guess if the Freightliner concept had arrived in say the mid 1930's, the 2-8-2 or 2-8-4 might have had it's uses.

[Corbs]

6 hours ago, rockershovel said:

I can’t quite find the designs with the trailing bogie credible - apart from anything else, the tenders look too small? Austerity, LNER and BR experience seems to demonstrate that the 2-8-2 and 2-10-0 represent the limit of usable size for U.K. conditions, with the 2-8-0 the biggest type for most practical uses in the pre-nationalisation era. 

They’re imaginary 

[Corbs]

I jest, of course. Pretty much everything on this thread has a good reason for not existing

 

I dug out ‘locomotive panorama’, here’s the diagram of the 4-6-4 loco and part of the accompanying text (I don’t really want to post the rest due to copyright, but this should give some insight).

Cox states that the combustion chamber would be eliminated, the frame would be bar frames from the coupled wheels back at least, but that the achilles heel would be the build up of ash in the pan, which had the potential to make a non-stop run from London to Glasgow impossible.

[Clive Mortimore]

1 hour ago, Corbs said:

They’re imaginary 

Dear Mr Corbs

 

You can't do that, you have broken the unwritten RMweb law that states after 3 post you should totally ignore the subject title.....imaginary locos on a thread about imaginary locos what ever next.

 

I really liked the video on how you "took " the photo of the Crosti-Caprotti standard five.

[RLBH]

40 minutes ago, Corbs said:

Cox states that the combustion chamber would be eliminated, the frame would be bar frames from the coupled wheels back at least, but that the achilles heel would be the build up of ash in the pan, which had the potential to make a non-stop run from London to Glasgow impossible.

From Chronicles of Steam (which arrived yesterday!) it was anticipated that an American-style Delta truck would be needed for the largest possible ashpan capacity. Curve radius would be restricted to 10 chains rather than the 6 chains of lesser locomotives to further maximise ashpan capacity - and, I suspect, to prevent them from spreading the tracks too much. A 24-ton axle load was needed, but hammer blow was expected to be near zero since it was a four-cylinder locomotive; the precedent of 23 tons on the Turbomotive was cited.

 

The water consumption of that beast would be quite something - to avoid needing a much bigger tender, you'd  need every trough between Euston and Glasgow to be working. And probably a few extra ones north of Carlisle. Interestingly, the idea behind both the 4-6-4 and the 4-8-4 was that both were to be mixed-traffic machines, capable of hauling almost anything - the only exceptions being that the top-link passenger duties needed the speed of the 4-6-4, and heavy mineral work needed the 4-8-4. Implicit in this is an expectation that much more of the freight wagon fleet would be fitted with brakes.

 

The idea of running more, lighter trains with smaller locomotives was dismissed as whenever such things had been tried before the short trains inevitably needed making longer. A lesson that the modern railway could have done with remembering.  

[Corbs]

On that note, I don't think I'll ever forgive Virgin XC for replacing 125s with Voyagers.

 

Meanwhile, Swindon, the 1930s. Late at night, the telephone in the drawing office rings....

 

"Bonsoir Charles, c'est Andre. J'ai des idées pour votre locomotive 'King'..."

 

 

... Back to reality...

 

 

(steam chests enlarged, larger low pressure inside cylinders, double kylchap chimney, larger boiler, ACFI gear, 4-8-0 chassis extension, enlarged and smoothed steam feed pipes, cut down safety valve bonnet, outside walschaerts)

Edited July 12, 2019 by Corbs

[rockershovel]

1 hour ago, Corbs said:

On that note, I don't think I'll ever forgive Virgin XC for replacing 125s with Voyagers.

 

Meanwhile, Swindon, the 1930s. Late at night, the telephone in the drawing office rings....

 

"Bonsoir Charles, c'est Andre. J'ai des idées pour votre locomotive 'King'..."

 

 

... Back to reality...

 

 

(steam chests enlarged, larger low pressure inside cylinders, double kylchap chimney, larger boiler, ACFI gear, 4-8-0 chassis extension, enlarged and smoothed steam feed pipes, cut down safety valve bonnet)

 

See earlier comments regarding the lasting resentment engendered by the electrification of the ECML between Peterborough and London, causing WAGN to become a generic synonym for “taking advantage of a captive market”

[rockershovel]

3 hours ago, Corbs said:

They’re imaginary 

 

Ah, but there are all sorts of “imaginary”!

 

there are the never-wazzers like the LMS 4-6-4, LNER 4-8-2 and BR Standard 2-8-2 which have at least one wheel in reality. There are speculative types like the Caprotti Crosti 4-6-0 which weren’t built, but could have been. There are locos which are purely speculative, or plain unworkable. 

 

Then there are all sorts in between..

[Corbs]

I know mate I was just being flippant for fun

 

'tis why I posted the excerpt of the 4-6-4 and tender from Cox's book to show a basis in fact.... unlike the ChaKing  

Edited July 12, 2019 by Corbs

[62613]

12 hours ago, Corbs said:

I jest, of course. Pretty much everything on this thread has a good reason for not existing

 

I dug out ‘locomotive panorama’, here’s the diagram of the 4-6-4 loco and part of the accompanying text (I don’t really want to post the rest due to copyright, but this should give some insight).

Cox states that the combustion chamber would be eliminated, the frame would be bar frames from the coupled wheels back at least, but that the achilles heel would be the build up of ash in the pan, which had the potential to make a non-stop run from London to Glasgow impossible.

300 p.s.i. must be getting close to the maximum pressure you could get away with with a fire tube boiler that size.

[Compound2632]

12 hours ago, Corbs said:

‘locomotive panorama’,

 

 

Oh dear - in a moment of mild confusion I misread the title of Cox's book there as 'locomotive paranoia' which is what I sometimes get after seeing some of the fantastic beasts posted here.

[melmerby]

9 minutes ago, 62613 said:

300 p.s.i. must be getting close to the maximum pressure you could get away with with a fire tube boiler that size.

About par for USA practice in the 30s

UP 800 series (FEF-1,1937) has 300psi

[62613]

1 minute ago, melmerby said:

About par for USA practice in the 30s

UP 800 series (FEF-1,1937) has 300psi

Given maximum axle loads in the UK vis-a-vis the USA, I would think that quite possible.

[Gibbo675]

17 minutes ago, 62613 said:

300 p.s.i. must be getting close to the maximum pressure you could get away with with a fire tube boiler that size.

Hi 62613,

 

What makes you think that ?

Should the boiler be of welded steel construction then it would be plenty strong enough to with stand such a pressure with the added reduction in maintenance requirement over boilers using friction joints and copper fireboxes.

 

The main problem with the increase of boiler pressure is that once the steam has been super heated the oils of the day would not cope with lubricating the cylinders at the temperature that the steam reached.

 

Gibbo.

[RLBH]

19 minutes ago, 62613 said:

Given maximum axle loads in the UK vis-a-vis the USA, I would think that quite possible.

It's actually easier to have high pressure in a smaller boiler than a large one. To a reasonable approximation, the boiler wall thickness - and therefore weight - is given by

 

Thickness = Pressure * Boiler Radius / Material Strength

 

This is fundamentally why really high pressures need water tube boilers - the wall thicknesses become prohibitive otherwise.

[62613]

31 minutes ago, RLBH said:

It's actually easier to have high pressure in a smaller boiler than a large one. To a reasonable approximation, the boiler wall thickness - and therefore weight - is given by

 

Thickness = Pressure * Boiler Radius / Material Strength

 

This is fundamentally why really high pressures need water tube boilers - the wall thicknesses become prohibitive otherwise.

That's what I was on about. I think the general description when I was at college was "Hoop stresses". Yes, it's much easier to press a 2" diameter tube to 600 p.s.i. 

[AlfaZagato]

Instead of welding the boiler, how about a one-piece extruded boiler?

 

Also, I used to fantastic ideas of steam-powered airships with different alloys for boiler material.   Are either aluminum or titanium, or alloys thereof, suitable for pressure vessels at any serious push?

[Northmoor]

7 minutes ago, AlfaZagato said:

Instead of welding the boiler, how about a one-piece extruded boiler?

 

Also, I used to fantastic ideas of steam-powered airships with different alloys for boiler material.   Are either aluminum or titanium, or alloys thereof, suitable for pressure vessels at any serious push?

It's over 25 years since I studied this, but I think that would be less effective because of the grain structure.  On an extruded tube the greater tensile strength is lengthways, whereas for a pressure vessel you want the maximum strength to be circumferential.  That's why boilers are made from sections of plate rolled into rings.

[rodent279]

7 minutes ago, Northmoor said:

It's over 25 years since I studied this, but I think that would be less effective because of the grain structure.  On an extruded tube the greater tensile strength is lengthways, whereas for a pressure vessel you want the maximum strength to be circumferential.  That's why boilers are made from sections of plate rolled into rings.

Aren't tubes extruded? Would water tube boilers have extruded pressure vessels, or would they be of conventional boiler plate?