Imaginary Locomotives

[The Johnster]

6 hours ago, Compound2632 said:

 

But was it excessive, or less economic than the alternative of under-utilised larger engines? Can you produce figures to support your criticism? 

 

 

[Embedded link to Warwickshire Railways image lnwr_tam1237. The train is the 2pm "Corridor", the afternoon Anglo-Scottish express, admittedly a rather heavier proposition than any Midland express train.]

But was this train booked to be double headed?  I ask because that is a different kettle of fish to it being piloted on that particular occasion because it was overloaded, and different again from one of the locos working home attached to a train to save a path and contribute something useful into the bargain.  
 

If a train is regularly double headed, and many on the Midland and the LNW were, it is surely an indication that a more powerful loco is needed.  The Midland never really solved it’s double-heading problem, but with it’s biggest engine being the 4P compound presumably could have easily enough had their board been amenable to the idea.  The LNW tried unsuccessfully with the Claughtons, which were replaced by the Royal Scots; these hardly covered themselves with the glory demanded of them but could at least haul the trains singly!  If the biggest loco you can build still needs double heading, you’re in trouble…
 

 

[toby_tl10]

8 hours ago, sncf231e said:

Regards

Fred

Reminds me of Henry from the Railway Series. If you remove those steps and put the driving wheels closer, it might look better.

 

I agree with rodent279, it might still be a poor steamer, just like Henry.

[Compound2632]

3 hours ago, The Johnster said:

If the biggest loco you can build still needs double heading, you’re in trouble…

 

Well, that's the LNWR in the 20th century...

[Yarravalleymodeller]

2 minutes ago, toby_tl10 said:

Reminds me of Henry from the Railway Series. If you remove those steps and put the driving wheels closer, it might look better.

 

I agree with rodent279, it might still be a poor steamer, just like Henry.

I think there would be comedy value in the 4-10-2 variant but still with a tiny low sided 6 wheel tender

[Gareth 73]

6 hours ago, john new said:

Big problem is the firebox needs to be at the downhill end.

Easy solved It works tender first 

[Compound2632]

28 minutes ago, toby_tl10 said:

If you remove those steps and put the driving wheels closer, it might look better.

 

It's an Ivatt Atlantic - the driving wheels are so close together the flanges almost touch. Driving wheels 6' 7½" diameter, wheelbase 6' 10"; the model undoubtedly spreads the wheelbase a bit to cope with over-scale flanges, a dodge hidden by the steps. The Gresley A1/A3 had 6' 8" drivers with 7' 3" + 7' 3" coupled wheelbase; the proposed GN pacific of 1915 had 7' 0" + 7' 0" coupled wheelbase.

 

So why does the "Ivatt pacific" look so wrong?

 

 

Edited December 5, 2022 by Compound2632

[DK123GWR]

15 minutes ago, Gareth 73 said:

Easy solved It works tender first 

But then being 'cab forwards' only makes the driver's view worse!

[rockershovel]

32 minutes ago, Compound2632 said:

 

It's an Ivatt Atlantic - the driving wheels are so close together the flanges almost touch. Driving wheels 6' 7½" diameter, wheelbase 6' 10"; the model undoubtedly spreads the wheelbase a bit to cope with over-scale flanges, a dodge hidden by the steps. The Gresley A1/A3 had 6' 8" drivers with 7' 3" + 7' 3" coupled wheelbase; the proposed GN pacific of 1915 had 7' 0" + 7' 0" coupled wheelbase.

 

So why does the "Ivatt pacific" look so wrong?

 

 

.... because the Ivatt Atlantic is a classic example of the engineering dictum that "if it looks right, then it is right". 

[tythatguy1312]

8 hours ago, PhilJ W said:

What about an oil fired 9F with cab forward and a tender attached to the smokebox end? Also a cab could be accommodated in the tender to avoid turning the locomotive.

I'm starting to suspect that cab-forwards radiate an energy of "well, why not?" because I have yet to find a single good use-case for one in the UK, but the idea of a proper one (IE: not from a tramway in the countryside) is undeniably an attractive proposal, particularly for their increased forward visibility. I imagine that if everyone went sufficiently mad enough to build a truly modern steam locomotive, particularly one not of the Standard 5's lineage, then it'd be an oil-fired cab forward for that exact advantage.

As for whether it'd work with the 9f? IDK probably, but it may need a speedometer to actually keep the thing below the speed limit. Oil fired locos were notably better steamers and the cab would likely offer less air resistance than the front of a 9f, making it even more prone to fast running.

Edited December 5, 2022 by tythatguy1312

[rodent279]

39 minutes ago, rockershovel said:

.... because the Ivatt Atlantic is a classic example of the engineering dictum that "if it looks right, then it is right". 

The boiler just looks too long and thin to be an effective steam raiser. TGB's main problems AIUI were that it was a shy steam raiser, and too long and heavy for all but London-Bristol.

Ivatt Atlantics were good engines, capable of being thrashed mercilessly, and still holding their own on certain jobs like London-Leeds Pullmans into the 1930's. A Gresley Pacific is not simply a stretched Ivatt Atlantic, it is a very different design.

Edited December 5, 2022 by rodent279

[melmoth]

1 hour ago, Compound2632 said:

 

So why does the "Ivatt pacific" look so wrong?

 

 

Perhaps because it's a very good illustration of what beset a large number of locomotive designers in the early 20th century: a stretched version of a successful four coupled engine does not automatically make a successful six coupled engine. Off the top of my head, I'd suggest most of Dugald Drummond's 460s, some of J.G. Robinsons, The Great Bear, Vincent Raven's pacifics, several LNWR types, and possibly the Caledonian's Cardean class as evidence. The notable omissions from the list are David Jones's Highland Goods (but what would they have been an enlargement of?) and Churchward's 460s.

 

This is a very broad-brush answer with plenty of scope for disagreement 🙂

[Gareth 73]

1 hour ago, DK123GWR said:

But then being 'cab forwards' only makes the driver's view worse!

Because it was mentioned in the post that the tender has a cab to save turning the loco. Hence putting the firebox at the down hill end

[Compound2632]

1 hour ago, melmoth said:

 

Perhaps because it's a very good illustration of what beset a large number of locomotive designers in the early 20th century: a stretched version of a successful four coupled engine does not automatically make a successful six coupled engine. Off the top of my head, I'd suggest most of Dugald Drummond's 460s, some of J.G. Robinsons, The Great Bear, Vincent Raven's pacifics, several LNWR types, and possibly the Caledonian's Cardean class as evidence. The notable omissions from the list are David Jones's Highland Goods (but what would they have been an enlargement of?) and Churchward's 460s.

 

This is a very broad-brush answer with plenty of scope for disagreement 🙂

 

Absolutely agree. Churchward cracked the 4-6-0 problem; no other 4-6-0 of the early years of the 20th century was really satisfactory - especially not those trying to enlarge the brilliant Drummond 4-4-0 formula - McIntosh's as well as Drummond's own attempts. Peter Drummond had a bit more success, because he based his Castle on the Jones Goods. Perhaps the Midland was wise not to go down the 4-6-0 route - though Deeley had had a compound 4-6-0 drawn up.

 

I would omit Raven's pacifics from that list; they were just as good (or bad) as Gresley's first pacifics but didn't have the opportunity to be developed as the Gresley ones were.

 

 

[DenysW]

7 hours ago, The Johnster said:

If a train is regularly double headed, and many on the Midland and the LNW were, it is surely an indication that a more powerful loco is needed.

Possibly, but not certainly. If your enterprise has a policy of having very few, very numerous, classes that stay in production for long periods of time (but tolerating the odd exceptional class) and only one or two routes demand a bigger loco, you might choose to double-head until/unless the demand for bigger locos spreads across more of your network. Especially if it's on the passenger side of the business and 2/3rds of what you are paid to transport is freight.

 

I put the Midland into this category. Then it was Government-run during WW1, then force-merged with two similar-sized companies that had different histories, and types of route, and the resulting unwieldy giant was also landed with a flock of various-sized other companies, all appreciably smaller and mostly poorer. And all with fleets that were not the same as the three largest constituent companies, so interoperability was challenging. No wonder, even if you follow a simplistic view that Midlandisation triumphed and was implemented everywhere, that the step-change to the next-size-up from 4Ps and 4Fs was delayed into the late 1920s and the 1930s, and that it happened in more than one step.

[Compound2632]

11 minutes ago, DenysW said:

I put the Midland into this category. Then it was Government-run during WW1, then force-merged with two similar-sized companies that had different histories, and types of route, and the resulting unwieldy giant was also landed with a flock of various-sized other companies, all appreciably smaller and mostly poorer. And all with fleets that were not the same as the three largest constituent companies, so interoperability was challenging. No wonder, even if you follow a simplistic view that Midlandisation triumphed and was implemented everywhere, that the step-change to the next-size-up from 4Ps and 4Fs was delayed into the late 1920s and the 1930s, and that it happened in more than one step.

 

Unhistorical rot, I'm finally forced to say. What you overlook is that the LNWR, L&YR, and MR were moving towards a working union before the Great War, starting with various traffic pooling agreements in 1908. (The GCR, GER, and GNR started down a similar route at the same time.) So the LMS was a foregone conclusion over a decade before the Railways Act, 1921. I also think you need to examine how the railways were actually operated during the Great War - what do you understand by "Government-run"?

 

As to early LMS locomotive policy, I do have to suggest that you carefully read the two books I mentioned earlier:

• D. Hunt, J. Jennison and R.J. Essery, LMS Locomotive Profiles No. 15 The ‘Royal Scots’ (Wild Swan, 2019)
• J. Jennison, A detailed history of the Patriot Class 4-6-0s (RCTS, 2018)

to get a proper understanding of what happened and why, instead of peddling folklore about Midland triumphalism. Apologies for writing so forthrightly; I appreciate that you are not the originator of the misconceptions you repeat but simply the victim of generations of misinformation. 

Edited December 5, 2022 by Compound2632

[DenysW]

11 hours ago, rodent279 said:

 

12 hours ago, 62613 said:

That's an awfully long boiler!

Looks like it would fall into the same trap as The Great Bear.  Boiler too long, firebox too small, no combustion chamber, too heavy.

Maybe just needs every detail of the invisible internal parts of the design re-visited. If very long boilers (by UK criteria) were an automatic fail-to-steam then the 6000 hp American Mallets would also have failed. The Big Boys and the Southern Pacific cab-forwards were 120-135' long, nearly twice maximum UK practice. No, I think that heat-exchanger tube diameters, the power behind drafting, the details of the grate, etc. etc. all need re-optimising then you can judge what length of boiler is too long.

 

Not something that could be done with the Great Bear having to be in revenue service and used as a Swindon success in company publicity. Also something that's easier if you are Baldwin or ALCO and are gradually building progressively longer boilers, and not trying to do the lot in one step.

[Flying Pig]

5 hours ago, Compound2632 said:

So why does the "Ivatt pacific" look so wrong?

 

 

Because the boiler is very obviously too long.  The boiler of an A1 began just in front of the first coupled wheel and the external boiler-firebox join was only a shade behind the rear coupled axle, with the front corners of the firebox strongly sloped.  This loco has a boiler that extends well over the front bogie and the front corners of the firebox are nearly vertical.

 

Interestingly, the Raven Pacifics had similar boiler proprotions and don't look right to me either.

[Flying Pig]

2 hours ago, DenysW said:

The Big Boys and the Southern Pacific cab-forwards were 120-135' long, nearly twice maximum UK practice. No, I think that heat-exchanger tube diameters, the power behind drafting, the details of the grate, etc. etc. all need re-optimising then you can judge what length of boiler is too long.

 

 

Grate areas were much bigger too, so the thermal power being absorbed by the boiler was significantly higher.

[DenysW]

2 hours ago, Compound2632 said:

Apologies for writing so forthrightly;

But not rudely, so no need to apologise.

 

I don't disagree with almost anything you wrote. I do believe that the Midland, L&NW, and L&Y all had different cultures and there would have been clashes as a result on the way to some approximation of uniformity - irrespective of the driving force behind the union (external or internal).

[Compound2632]

40 minutes ago, Flying Pig said:

Interestingly, the Raven Pacifics had similar boiler proprotions and don't look right to me either.

 

Certainly the firebox is inadequately proportioned in the fake Ivatt pacific, although the proportions are not so far off the 1915 Gresley proposal. I suspect a lot of it has to do with the parallel boiler making the front end look much more massive than one is used to with the taper boiler of the classic Gresley pacific; this would explain why you find the Raven pacific wrong-looking too. Which goes to show that there's a lot of prejudice based on what one is familiar with; there's no evidence that there was anything particularly wrong with the steaming of the Raven boilers, is there? I seem to recall a discussion on here in which it was confirmed that trials in 1923 or thereabouts had shown the Raven pacific boiler to steam better than that of the first Gresley pacifics? (Need some fact checking there.] 

[rodent279]

2 hours ago, DenysW said:

Maybe just needs every detail of the invisible internal parts of the design re-visited. If very long boilers (by UK criteria) were an automatic fail-to-steam then the 6000 hp American Mallets would also have failed. The Big Boys and the Southern Pacific cab-forwards were 120-135' long, nearly twice maximum UK practice. No, I think that heat-exchanger tube diameters, the power behind drafting, the details of the grate, etc. etc. all need re-optimising then you can judge what length of boiler is too long.

 

Not something that could be done with the Great Bear having to be in revenue service and used as a Swindon success in company publicity. Also something that's easier if you are Baldwin or ALCO and are gradually building progressively longer boilers, and not trying to do the lot in one step.

Yes, it's not so much the length of the boiler in itself, as it's length in relation to the size of firebox, combustion chamber or lack thereof, size & number of firetubes etc.

 

Maybe some of those early C20th locomotive engineers should have read Zen & the Art of Steam Locomotive Boiler Engineering Motorcycle Maintenance?

[rodent279]

9 minutes ago, Compound2632 said:

 

Certainly the firebox is inadequately proportioned in the fake Ivatt pacific, although the proportions are not so far off the 1915 Gresley proposal. I suspect a lot of it has to do with the parallel boiler making the front end look much more massive than one is used to with the taper boiler of the classic Gresley pacific; this would explain why you find the Raven pacific wrong-looking too. Which goes to show that there's a lot of prejudice based on what one is familiar with; there's no evidence that there was anything particularly wrong with the steaming of the Raven boilers, is there? I seem to recall a discussion on here in which it was confirmed that trials in 1923 or thereabouts had shown the Raven pacific boiler to steam better than that of the first Gresley pacifics? (Need some fact checking there.] 

According to Nock in his book on Gresley Pacifics, trials between the two types were done, and neither showed a marked superiority over the other, except that the Raven machines were a little heavier on coal.

The short con rod & drive to the leading coupled wheels on the Raven pacifics also makes them look a little longer, and less "balanced " visually .

Edited December 5, 2022 by rodent279

[sncf231e]

14 hours ago, 62613 said:

That's an awfully long boiler!

Maybe this boiler (of another modified Atlantic) is too short?

 

 

Regards

Fred

 

[rodent279]

Since this thread is about imaginary locomotives,  how about a Raven Pacific derived A4?

[sncf231e]

7 hours ago, Compound2632 said:

So why does the "Ivatt pacific" look so wrong?

 

 

Does a Gresley Atlantic look better?

Regards

Fred