Imaginary Locomotives

[DenysW]

2 hours ago, Yarravalleymodeller said:

You're only having a fiddle with 30% odd of stuff that makes up the design and none of it seriously in depth in order to achieve one from the other. 

If there's one thing I've learned from reading about steam locomotives, it's that every bl**dy detail needs to be reviewed once you've made even a modest-looking change. Otherwise you re-visit experiences like "it turned out to be much harder to go from a 4-4-0 to a 4-6-0 than anyone expected" or "but the entire class steamed poorly" etc.. Even from cream-of-the-crop designers like Anton Hammel and Heinrich Leppla at Maffei*.

 

* Chosen so as not to dip into loyalties from Grouped and Pre-Grouping UK companies.

Edited December 7, 2022 by DenysW
Add footnote

[Yarravalleymodeller]

40 minutes ago, DenysW said:

If there's one thing I've learned from reading about steam locomotives, it's that every bl**dy detail needs to be reviewed once you've made even a modest-looking change. Otherwise you re-visit experiences like "it turned out to be much harder to go from a 4-4-0 to a 4-6-0 than anyone expected" or "but the entire class steamed poorly" etc.. Even from cream-of-the-crop designers like Anton Hammel and Heinrich Leppla at Maffei*.

 

* Chosen so as not to dip into loyalties from Grouped and Pre-Grouping UK companies.

Yeah I do not deny there is a bit of that about it, however there is also a dose of our modern view point of how hard it would be stepping in because today it would be hard to do economically speaking and hard to justify economically speaking but go back to around the time of grouping and frankly far more objectively stupid things were experimented with which had absolutely no hope. 

 

Was also largely the case that many locos and even classes went through what would now be called "iterative design" rather than being designed well from the start. If you ever read a report of a loco working with no issues appearing from drawing board to operational prototype then these are more than likely an outright lie.

1 hour ago, Compound2632 said:

 

Yes really. The firebox position relative to the coupled axles is completely different. Likewise if one compares a 4-4-2 and a 4-4-2T or a 4-6-2 and a 4-6-2T.

 

And? The weight distribution can be solved any number of ways, the simplest being a counterweight, the next being counterweight plus springing calibrated to account for it. I've seen pretty much this exact problem play out in large scale miniature locos being converted from briggs boiler to proper locomotive boiler a similar messing about of the weight and it's distribution. I speak from some modest experience of messing with stuff when I say it really wouldn't be a HUGE challenge

[rodent279]

58 minutes ago, DenysW said:

If there's one thing I've learned from reading about steam locomotives, it's that every bl**dy detail needs to be reviewed once you've made even a modest-looking change. Otherwise you re-visit experiences like "it turned out to be much harder to go from a 4-4-0 to a 4-6-0 than anyone expected" or "but the entire class steamed poorly" etc.. Even from cream-of-the-crop designers like Anton Hammel and Heinrich Leppla at Maffei*.

 

* Chosen so as not to dip into loyalties from Grouped and Pre-Grouping UK companies.

We're back to Zen & the Art of Steam Locomotive Design.

You can only go so far in looking at parts of the system in isolation. You have to consider the system as a whole, and work out the impact of a change in any one part on other parts of the system.

[Yarravalleymodeller]

5 minutes ago, rodent279 said:

We're back to Zen & the Art of Steam Locomotive Design.

You can only go so far in looking at parts of the system in isolation. You have to consider the system as a whole, and work out the impact of a change in any one part on other parts of the system.

And in large part at least back then the only way to do this was build it and see, then mess with component parts. The line between failure and success being how much you are willing to mess around before either scrapping it or winding it back to something more convenstional and known

[DenysW]

1 hour ago, rodent279 said:

work out the impact of a change in any one part on other parts of the system.

An anecdote from automotive. On adding front-screen defrosting to an American brand of luxury car, this apparently simple, local, upgrade, triggered 700 other changes, including the control of the idle rate of the car.

[sncf231e]

2 hours ago, DenysW said:

"it turned out to be much harder to go from a 4-4-0 to a 4-6-0 than anyone expected"

It is not hard to go from a 4-6-2 to a 4-8-2:

Regards

Fred

[DenysW]

2 hours ago, sncf231e said:

It is not hard to go from a 4-6-2 to a 4-8-2:

If you have one, hop in your time machine and tell Gresley the P2s have been superseded by this Super-Duck.

[tythatguy1312]

6 hours ago, sncf231e said:

It is not hard to go from a 4-6-2 to a 4-8-2:

That always did confuse me. The jump from 4 coupled to 6 coupled machines (barring 0-6-0's) seems to have been remarkably painful in comparison to the jump from 6 coupled to 8 coupled machines. The LNER P2's could be a good example of what not to do (overly rigid wheelbase, generally individualistic design, reliability issues and an unpleasant appearance) but the jump seems to have been a lot easier. That being said it's rather surprising that most 4-8-2's, at least in the US, were consigned to freight usage... which raises the question of how Union Pacific jumped from 2-8-2's to 4-12-2's with little issue.

[AlfaZagato]

13 minutes ago, tythatguy1312 said:

 how Union Pacific jumped from 2-8-2's to 4-12-2's with little issue.

UP was needy and Alco insane.

 

Fun fact, the 4-12-2s, UP class 9000, were the only American locomotive to have Gresley gear, and the largest type in any country to have such gear.

[tythatguy1312]

1 hour ago, AlfaZagato said:

the largest type in any country to have such gear.

considering that they're among the biggest rigid locomotives ever constructed, I doubt that needed to be said.

[sncf231e]

2 hours ago, AlfaZagato said:

Fun fact, the 4-12-2s, UP class 9000, were the only American locomotive to have Gresley gear, and the largest type in any country to have such gear.

Regards

Fred

[Yarravalleymodeller]

7 hours ago, tythatguy1312 said:

That always did confuse me. The jump from 4 coupled to 6 coupled machines (barring 0-6-0's) seems to have been remarkably painful in comparison to the jump from 6 coupled to 8 coupled machines. The LNER P2's could be a good example of what not to do (overly rigid wheelbase, generally individualistic design, reliability issues and an unpleasant appearance) but the jump seems to have been a lot easier. That being said it's rather surprising that most 4-8-2's, at least in the US, were consigned to freight usage... which raises the question of how Union Pacific jumped from 2-8-2's to 4-12-2's with little issue.

The jump from 6 to 8 coupled express passenger engines never really happened and was pretty much all pain, in the UK anyway. 

 

The jump from 4-4-0 to 4-6-0 broadly speaking wasn't painful in the slightest, several of the initial efforts at 4-6-0s lasted  into Nationalisation which is testiment to how good they were when given appropriate work.

 

The real issue with them is that by the time most of them appeared they were already on the way to being out of date in terms of the jobs they were intended for. An issue that also plagued the jump from 2-2-0 to 2-2-2 to 0-6-0. You build a loco capable of pulling a train of X weight at X rate. By the time you have built it the trains are Y weight or run at Y rate. Was a constant battle to keep up which is partly why so many schemes that we scoff at today as obviously fraudulent or truth bending made it through to being prototyped. If you're constantly trying to keep up you'll take a punt on any monorail salesman and his incredible device to improve efficiencies 400%.😅

[Compound2632]

5 hours ago, Yarravalleymodeller said:

The jump from 4-4-0 to 4-6-0 broadly speaking wasn't painful in the slightest, several of the initial efforts at 4-6-0s lasted  into Nationalisation which is testiment to how good they were when given appropriate work.

 

I really don't see how you can say that, given even only the previous remarks on this thread. Apart from the Great Western Saints, I really don't see a 4-6-0 class of the first decade of the 20th century that made it to nationalisation without considerable rebuilding. There were many notable failures, the worst cases being those of the Drummond school. What classes are you thinking of?

[PhilJ W]

The B12's were a good example of a 4-6-0 that was developed from a 4-4-0 (the Clauds) and were quite successful. Not all were rebuilt and there were further examples constructed post grouping.

[Yarravalleymodeller]

2 hours ago, Compound2632 said:

 

I really don't see how you can say that, given even only the previous remarks on this thread. Apart from the Great Western Saints, I really don't see a 4-6-0 class of the first decade of the 20th century that made it to nationalisation without considerable rebuilding. There were many notable failures, the worst cases being those of the Drummond school. What classes are you thinking of?

Lets start with the first, jones goods, made it to 1940 in service, so admired it was never looked on as some scrap metal as quite a few other locos were in the depths of war Also technically ran under BR. 

 

The GCR class 8, made it to nationalisation no problem, go just a year past the arbitrary 1910 cut off and we find what becomes the B12s which were good to begin with, so good they made it to the LNER largely unmodified. 

 

The LNWR examples, so bad they built them in the 100s, multiple hundreds in some cases. If something is so absolutely bad and a critical failure why do you build 200 of them and keep them in service for well over decade... you'd imagine someone would step in and say "no... stop... think of the children, how can we make this grave mistake"

 

Even the claughtons, once you accept the poor valve events at speed, are not useless engines and thats sorta how they lasted out until they did. If we just go oh the valve events were poor at some speeds so loco totally useless then oh boy Mallard is a useless heap of junk because it suffers poor valve events up to a point. This is something we just love to do with railways, particularly locos, is focus very sharply on some critism levelled at some really rarher minor issue that doesn't constitute a total failure, as evidenced by a decade or more of working life, and say "bad". I guess the carriage equivalent would be me saying all MK1s are awful because the windows always seemed a bit sticky 😅just ignore completely the millions of journeys they enabled because the window mechanism was sticky.

Edited December 8, 2022 by Yarravalleymodeller

[Compound2632]

1 hour ago, Yarravalleymodeller said:

The LNWR examples, so bad they built them in the 100s, multiple hundreds in some cases. If something is so absolutely bad and a critical failure why do you build 200 of them and keep them in service for well over decade... you'd imagine someone would step in and say "no... stop... think of the children, how can we make this grave mistake"

 

If one takes the Churchward Saint as a yardstick of success - which is, admittedly, setting a very high bar, then the Whale Experiments were less than a success. There is Churchward's famous reposte to one of the GWR directors who complained of the relative cost of 4-6-0s from Swindon and from Crewe - one would like to have seen that put to the test! Whale's engines were very heavy on coal, which was unfortunate in the light of the labour unrest of the period. Bowen-Cooke addressed that issue with superheating, leading to the Prince of Wales class. Once could argue that they were the most successful of pre-grouping 4-6-0s and were being built right up to and beyond the grouping; their numerical superiority over the Saints (and that of the Claughtons over the Stars) is simply an indicator of the vast size of the LNWR's passenger and fast freight business over that of the Great Western. But by 1930 there was a clear need for an "Improved Prince of Wales", which in due course appeared as the Class 5MT.

[Yarravalleymodeller]

1 minute ago, Compound2632 said:

 

If one takes the Churchward Saint as a yardstick of success - which is, admittedly, setting a very high bar, then the Whale Experiments were less than a success. There is Churchward's famous reposte to one of the GWR directors who complained of the relative cost of 4-6-0s from Swindon and from Crewe - one would like to have seen that put to the test! Whale's engines were very heavy on coal, which was unfortunate in the light of the labour unrest of the period. Bowen-Cooke addressed that issue with superheating, leading to the Prince of Wales class. Once could argue that they were the most successful of pre-grouping 4-6-0s and were being built right up to and beyond the grouping; their numerical superiority over the Saints (and that of the Claughtons over the Stars) is simply an indicator of the vast size of the LNWR's passenger and fast freight business over that of the Great Western. But by 1930 there was a clear need for an "Improved Prince of Wales", which in due course appeared as the Class 5MT.

Hindsight is the great twister of reality. 

 

I don't think any railway particularly foresaw labour disputes or rising coal prices, while this may have not been ideal for the balance sheet or indeed the firemans back does it mean they were bad locomotives that couldn't do the job. Nope. 

 

Is your car bad because oil prices went up? 

 

Is the plane badly designed because the price of the gate at the airport went up and you got the knock on cost?

 

As long as it goes, as long as it doesn't actively lose money just loses some % of profitability for the railway even these business based arguments don't make the design bad they just make it less than perfect at that moment in time.

 

More interestingly, name a perfect loco capable of weathering any economic condition or traffic demand, I don't think one exists, even the mighty GWR couldn't really do that.

[Compound2632]

2 minutes ago, Yarravalleymodeller said:

Hindsight is the great twister of reality. 

 

Certainly. I don't think that at the turn of the century, any of the railway companies foresaw that the era of continuous growth was over and that they were on the brink of the long downward spiral of rising costs and diminishing returns. Whoever invented the corridor carriage had a lot to answer for...

[Yarravalleymodeller]

18 minutes ago, Compound2632 said:

 

Certainly. I don't think that at the turn of the century, any of the railway companies foresaw that the era of continuous growth was over and that they were on the brink of the long downward spiral of rising costs and diminishing returns. Whoever invented the corridor carriage had a lot to answer for...

As a quick side note, before I start work, there's human factors to consider whenever we talk coal consumption, humans are very much creatures of habit. If you get used to firing in a particular way you tend to get stuck firing that way. I've witnessed this play out with preservation era firemen coming for a play on locos they don't usually use. 

 

All it takes is for one design to supersede another and the firemen to remain stuck in their ways and you can have an apparent poor coal consumption caused by them laying it on thick when not needed. Might not seem much at first glance but add it up over the sheer number of trips and yes you end up with a big bill for coal. 

 

Equaly applies to steaming capabilities, the person controlling use of that steam can be doing so in a poorly managed way and if you apply that to many people you end up with reports of poor steaming. 

 

Sure if we fire something up tomorrow when I go play trains then there would be among the people there those who can get a long way on a little and those who go nowhere for a full tank of water and all the coal. It's a very difficult one to judge even by the account books unless they are wildly consistently terrible numbers.

 

Also other things like size of the coal play into it but again, whole other rabbit hole to go down to try and find the truth to any of it

[billbedford]

4 hours ago, Compound2632 said:

 

I really don't see how you can say that, given even only the previous remarks on this thread. Apart from the Great Western Saints, I really don't see a 4-6-0 class of the first decade of the 20th century that made it to nationalisation without considerable rebuilding. There were many notable failures, the worst cases being those of the Drummond school. 

 

This leaves out a couple of things. First most pre-1910 4-6-0s were built in penny numbers so they were prone to their class being withdrawn as a cost-cutting expediency. Also boilers built for these engines would be expected to be replaced during the 30s, so a decision had to be made whether to fit a more modern, 'standard', boiler or withdraw the locos as the boilers needed replacement. 

Finally there was a cull of most of the existing 4-6-0 classes after WW2 by which time all of the companies had built their own 'standard' types, B1, Black Five, West Country*, and Hall, which were seen as more efficient and economical. 

 

*Yes, I know they weren't 4-6-0s, but...

[tythatguy1312]

Speaking of spam cans, it'll always amuse me how the Light Pacifics were repeatedly scaled up (IIRC they started development as 2-6-0's) whilst the Merchant Navy's were scaled down (I think they began as 4-8-2's), which raises the amusing idea as to how they would've gone had they been built to their original size and some terrifying thoughts involving The Leader.

[Northmoor]

10 hours ago, Yarravalleymodeller said:

The LNWR examples, so bad they built them in the 100s, multiple hundreds in some cases. If something is so absolutely bad and a critical failure why do you build 200 of them and keep them in service for well over decade... you'd imagine someone would step in and say "no... stop... think of the children, how can we make this grave mistake"

 

Even the claughtons, once you accept the poor valve events at speed, are not useless engines and thats sorta how they lasted out until they did. If we just go oh the valve events were poor at some speeds so loco totally useless then oh boy Mallard is a useless heap of junk because it suffers poor valve events up to a point. This is something we just love to do with railways, particularly locos, is focus very sharply on some critism levelled at some really rarher minor issue that doesn't constitute a total failure, as evidenced by a decade or more of working life, and say "bad". I guess the carriage equivalent would be me saying all MK1s are awful because the windows always seemed a bit sticky 😅just ignore completely the millions of journeys they enabled because the window mechanism was sticky.

Do you actually mean a Decade?  A loco with an operating life of only a decade really would be a failure, it would be withdrawn once the first boiler overhaul was due.  Locomotives were expected to operate for 30 years plus.

[Compound2632]

4 minutes ago, tythatguy1312 said:

the Light Pacifics were repeatedly scaled up (IIRC they started development as 2-6-0's) whilst the Merchant Navy's were scaled down (I think they began as 4-8-2's)

 

By rights, the two designs should have averaged out as 3-7-1s.

[tythatguy1312]

6 minutes ago, Compound2632 said:

 

By rights, the two designs should have averaged out as 3-7-1s.

didn't know the Listowel & Ballybunion was on the table for imaginary machines but I know at least 3 people who believed that their locomotives didn't actually exist, at least until I elaborated. To be fair those contraptions are closer to my sleep paralysis demon than a locomotive.

Edited December 8, 2022 by tythatguy1312

[Compound2632]

1 minute ago, Northmoor said:

Do you actually mean a Decade?  A loco with an operating life of only a decade really would be a failure, it would be withdrawn once the first boiler overhaul was due.  Locomotives were expected to operate for 30 years plus.

 

The Prince of Wales class was introduced in 1911, with the last batch appearing in 1922. Barring a handful of survivors to 1946-7, withdrawal dates were between 1933 and 1937, with operating lives of between 15 and 26 years - really not very long by any standards.