Imaginary Locomotives

[rockershovel]

6 hours ago, DenysW said:

Picture originally posted by Rockershovel on p 211.

 

 

Is it just me or does that just need to be  (sort-of) Garratt-ised to work? Get rid of one of the small wheelsets at the boiler/motive unit interface, and put a water tank around the big wheel and over the front wheel to weigh the front down for adhesion. Might be too long, still, of course, but now it's an inverse-Crampton, and they were adequate for light loads at speed.

Surely Cramptons would have a significant part of the overall weight on the drivers? Not a large weight, but more than this configuration? 

 

The best figures I can find, suggest a weight for a Crampton of 30 tons, suggesting an adhesion weight of around 10-12 tons? 

Edited December 12, 2021 by rockershovel

[DenysW]

The typical Crampton seems to have had one pair of (huge) driving wheels and 2-3 pairs of non-driving wheels, often of differing sizes (between axles!) to avoid snagging the non-driving axles on the mechanism. This is clearest (in my limited looking) on the photographs of NBR No. 55 after it had been rebuilt away from a Crampton  and renumbered 1009.

 

So yes, they still throw away an absurd - to modern eyes - fraction of the traction weight, But if you are designing for an 1830s Brunel or Stephenson billiard table, it's less of a disaster.

[The Johnster]

A sort of articulation had already be used in the 1820s on the Penydarren Tramroad, most famous for Trevithick's 1804 'steam trombone' built for a bet (typical of Cap'n Dick) but which was only used as a locomotive once, the rest of it's life being as a mobile steam engine pulled around the work by horses with the locomotive motion taken down.  It is not known how long it lasted in this condition, but apparently was in use for some time, and it may have been possible to convert it back to locomotive status fairly easily, but AFAIK this was never done.  The history of steam locomotives at Penydarren did not end with it, and several locomotives were in use by the 1820s, and some earlier, featuring articulation, twin foldable chimneys to go through a short tunnel, rack propulsion, and other innovations.  Suppliers were either local, Hirwaun Iron Co. or Neath Ironworks, involving the locomotives being delivered in parts by cart over the Mountain Hare pass on Hirwaun mountain, the route taken by the current A465 road, which must have been fun, or Stephenson's in Newcastle, which probably came by sea to Neath.

 

Penydarren, and later Dowlais, was as much a melting pot of steam locomotive ideas as the northeast of England and Leeds area, but overshadowed by it, so that this fascinating history is by and large unknown even in Wales.  Some of the other South Walian dramroads joined in the game as well, notably the Tredegar, which became absorbed into the Monmouth Railway and Canal Company.  Gauges varied, sometimes unintentionally, but were generally around the 4' ballpark, and the same problems with cast or wrought iron fishbelly rails, probably excascerbated by hammer blow where the engines were not geared, were experienced.

 

A big difference between the Penydarren and the English lines was that in South Wales the purpose was to serve ironworks, usually ore and limestone from the moors to the north and coking coal from local drifts, and in the case of the Penydarren and the Tredegar, finished iron products out to the south to the ports, Newport and Neath mostly.  The mine to port downhill trend was less prominent in South Wales, though in years to come it became prominent, and vital to the development of docks at Cardiff, Penarth, Barry, and Porthcawl.  What effect this had on the development of such steam locomotives as were used, and to what extent it differered from English types, is difficult to assess, but Penydarren had steep gradients and a tight tunnel, as well as the 'main line' from Merthyr down to Abercynon Basin, and it was this that undoubtedly led to the use of folding chimneys, rack locomoitves, and articulation. with varying degrees of success.

 

Some of this may have influenced Harrison with Hurricane. Brunel and his Bristolian confederates had close connections with the South Wales ironmasters, and this may have been the route by which Harrison obtained the idea of articulating his engine,  You can see what he was trying to do, as his layout means that the boiler does not restrict the size of the driving wheels, and big driving wheels were considered the best way to improve speed, ride, and the piston rate, desirable in those days of inadequate lubrication.  Gooch's big driver singles, and Pearson's on the Bristol & Exeter, featured very high pitched boilers which must have affected the ride, and young Trevithick at Crewe tried to get around this by putting Cornwall's boiler below the driving axle, with some success though the loco was later rebuilt more conventially.  But the lack of adhesive weight above the driven wheelset is obvious; it is actually quite difficult to make a steam locomotive that doesn't work at all once you have mastered the pressurised joints in the pipework, but Harrison came close with this thing, which had difficulty moving it's own weight, not far of what I'd class as 'not working'!

 

I'd love a working model of it, all the same...

[DenysW]

The Hurricane is one of the options in this year's quirky poll for suggestions for new RTR models, as is the Pearson Single. I fear both will founder, irrespective of rmweb support, on the difficulties of special track (or yet another scale that uses 16.5 mm track).

[DenysW]

The model shown in the quirky poll's Didcot link shows a little more weight on the drivers than I'd got from the 2D sketch: the cylinders and a counterweight. Still pretty hopeless though.

 

[PhilJ W]

24 minutes ago, DenysW said:

The model shown in the quirky poll's Didcot link shows a little more weight on the drivers than I'd got from the 2D sketch: the cylinders and a counterweight. Still pretty hopeless though.

 

Putting the driving wheels on the (extended) tender might have helped but would have caused other problems. I also see that the driver is on the driving portion facing the boiler. Was it intended to run tender first?

[DenysW]

I think there's some artistic licence here, and the modeller has added interest by adding a third figure. I'd assume the driver and stoker are at the tender end. I've never read that it normally runs backwards extra to its other eccentricities.

[PhilJ W]

2 hours ago, DenysW said:

I think there's some artistic licence here, and the modeller has added interest by adding a third figure. I'd assume the driver and stoker are at the tender end. I've never read that it normally runs backwards extra to its other eccentricities.

I see now that there's two figures on the footplate so the third figure must be the guy who steers it.

[DK123GWR]

29 minutes ago, PhilJ W said:

I see now that there's two figures on the footplate so the third figure must be the guy who steers it.

My sister insists that a train driver's job involves steering, and whenever we go to a museum she will point to any circular control (there are ususally loads to choose from on a steam loco) and 'prove' that she's right because it has a 'steering wheel'. She struggled to find one on the APT at Shildon!

[PhilJ W]

15 minutes ago, DK123GWR said:

My sister insists that a train driver's job involves steering, and whenever we go to a museum she will point to any circular control (there are ususally loads to choose from on a steam loco) and 'prove' that she's right because it has a 'steering wheel'. She struggled to find one on the APT at Shildon!

What would she make of a 'Shark' Ballast plough?

[billbedford]

23 minutes ago, DK123GWR said:

My sister insists that a train driver's job involves steering, and whenever we go to a museum she will point to any circular control

 

 

They were obvious on DMUs, but have been hidden since...

[Ohmisterporter]

I have seen trains in Switzerland with steering wheels.

[rockershovel]

14 hours ago, DenysW said:

I think there's some artistic licence here, and the modeller has added interest by adding a third figure. I'd assume the driver and stoker are at the tender end. I've never read that it normally runs backwards extra to its other eccentricities.

He must be the Captain, pacing the quarterdeck?

 

Given the proximity of the motion  and the lack of guards or splashers for the driving wheels, anyone at that end whilst under way would be a brave soul ...

Edited December 14, 2021 by rockershovel

[JimC]

I hadn't heard that any useful drawings of the Harrison/Hawthorn locomotives are extant, so should we assume that the model is largely speculative and not place too much weight on details?

 

 

 

Edited December 14, 2021 by JimC

[MikeOxon]

1 hour ago, JimC said:

I hadn't heard that any useful drawings of the Harrison/Hawthorn locomotives are extant, so should we assume that the model is largely speculative and not place too much weight on details?

 

There is a very detailed description of Harrison's engines in Nicholas Wood's 'Treatise on Rail-Roads', 3rd ed.,1838 with accompanying plates.  This book can be downloaded from the Internet Archive but unfortunately the plates have not been scanned clearly.

 

 

There are better versions of parts of this drawing reproduced in the Broad Gauge Society magazine 'Broadsheet' vol.77 and I made a drawing of the valve gear of 'Thunderer' shown below, which was also published in 'Broadsheet' vol.79.

 

I think there is sufficient information for an accurate model to be made.

 

Mike

[The Johnster]

A feature of Broad Gauge locomotives was that the driver was expected to be able to access most parts of the locomotive while it was in motion, hence the provision of railings on the edge of the running plate as opposed to the more usual arrangement of attaching them to the boiler with knobs.  The idea of walking around the outside of an Iron Duke at 70-odd mph in all weathers, with that big driving wheel whizzing around withing inches of your elbows, as if it was a stationary engine bolted to a factory floor, is pretty terrifying, but they made men of sterner stuff back then.  GW drivers objected to the provision of weatherboards on their engines because, they said, they compromised the view ahead, then objected to cabs because they feared that the increased warmth might make them drowsy, and when Churchward fitted County Carlow with a GE-type cab, they complained about that as well.

 

It is odd to our modern eyes that a driver should be required to leave his position at the controls where he has a good view of the road ahead to attend to the lubrication of various bits of spindizzy, and the Ais Gill accident on the Midland in 1913 involved a driver overrunning signals while he was away from the cab 'oiling around' and his fireman was distracted by a troublesome injector.  This was mentioned in the BoT report, as was the fact that such leaving of the cab was no longer neccessary in the days of wick lubricators.  Drivers continued to do so out of habit, though, and a feeling of responsibility for the well-being of the locomotive.  It was, by that time, a dangerous practice on modern locomotives with larger boilers which had not been designed with this in mind; the handrails were for use while the engine was stationary at the shed, not out on the road at speed, but the old-timers thought they were doing right, because they'd always done it that way and didn't trust the new-fangled wicks.  There is a lot of small c conservatism on railways.

 

[sir douglas]

 

Matthew Murray thought up the same idea of having the cylinders on a seperate chassis than the boiler but a few decades earlier. He was asked by the Stockton & Darlington to build them locomotives but replied that it had been over a decade since he (the Round Foundry) had last built locomotives but he still drew this up but never built. it was essentially his Middleton design but without the rack & pinion and split over 2 chassis' likely to reduce axle load

https://archives.imeche.org/archive/railways/1321922-matthew-murray?q=matthew murray

 

[whart57]

23 hours ago, The Johnster said:

GW drivers objected to the provision of weatherboards on their engines because, they said, they compromised the view ahead, then objected to cabs because they feared that the increased warmth might make them drowsy

 

Was it just the drivers? On the South Eastern the CME, Cudworth, didn't put cabs on his engines, arguing that it was better for drivers to be out in the open and that a stout macintosh was better than a cab roof. And yet over the years the weatherboard became a wrap-around affair, and tender weatherboards became the norm on engines expected to do a lot of tender-first working so the view ahead did become compromised. The last Cudworth engines built did get cabs but they were completed during the time of Richard Mansell who was temporary CME while the board argued over Cudworth's sacking and his replacement.

[john new]

5 hours ago, sir douglas said:

 

Matthew Murray thought up the same idea of having the cylinders on a seperate chassis than the boiler but a few decades earlier. He was asked by the Stockton & Darlington to build them locomotives but replied that it had been over a decade since he (the Round Foundry) had last built locomotives but he still drew this up but never built. it was essentially his Middleton design but without the rack & pinion and split over 2 chassis' likely to reduce axle load

https://archives.imeche.org/archive/railways/1321922-matthew-murray?q=matthew murray

 

Like the early suggestion of auto-feed firing using that hopper.

[MikeOxon]

3 hours ago, whart57 said:

Was it just the drivers? On the South Eastern the CME, Cudworth, didn't put cabs on his engines, arguing that it was better for drivers to be out in the open and that a stout macintosh was better than a cab roof.

Joseph Armstrong on the GWR apparently had similar views.  In the days when coke was the main fuel and carbon monoxide was being produced in quantity, it was probably wise to keep the footplate well ventilated!

[tythatguy1312]

whilst I'm fairly certain almost every possible other option has been extensively studied in this thread, I've been left wondering if geared locos could've caught on more for heavy shunting and long coal trains. Theoretically such a machine would reduce the workload on the engine when not accelerating, leading to cheaper running costs and better speed control. Plus, such a locomotive might be able to do the work that makes most locomotives do burnouts. It's known Thunderer had a geared drive to try and mitigate it's... adhesive shortcomings but it could've probably been more popular if seen on a mainline engine that actually had weight on the driving wheels besides the wheels themselves.

Edited December 19, 2021 by tythatguy1312

[The Johnster]

Stephensonian steam locomotives are already geared, in effect, by the size of their driving wheels and the relationship between that dimension and the crank throw.  This is why mineral engines have smaller diameter driving wheels than express passenger engines even when the boiler and engine are common to both.  Gearing in the sense of the engine driving a layshaft from which the drive is taken by cogs or bevel gears to the driving wheels was used on the Shay, Climax, and other types used on US logging railways, where a lightweight locomotive was required to haul heavy loads and speed was unimportant. 

 

Gearing as in the sense of driving at different gear ratios through a gearbox, while it was done with diesel mechanical dmus and some small diesel shunting engines would have been difficult to make work reliably in all but the smallest of steam locos, though Sentinel had a go at it.

 

Thunderer might have worked had there been better provison of tractive weight, and I am not certain if it was actually geared in the sense that speed was increased by gearing at the expense of power or power was increased by gearing at the expense of speed, or if it was simply driven by a layshaft and bevel cogs at a 1:1 ratio so that very large driving wheels could be used.  The thinking in those days was that a large driving wheel enabled the loco to run fast without too much in the way of piston speed and strokes per minute, which, in those days of inefficient lubrication of cylinder surfaces and bearings was sensible enough.  Big wheels also improved the ride over primitive track.

[tythatguy1312]

31 minutes ago, The Johnster said:

power was increased by gearing at the expense of speed

from what I've seen of Thunderer, this specific form is what I suspect was the case. It appears that the wheels drove a large gear that meshed with a smaller gear directly on the driving axle, which lead to increased tractive effort at the expense of speed, although I doubt an 0-4-0 needs much speed to begin with. It is this form of more complex yet theoretically more efficient gearing that I'm referring to, although more inspired by American geared locomotives than Brunel's Catastrophic Cavalcade.

[AlfaZagato]

The problems with geared steam, as in the American logging types, is both with the quality of machining available, and the use of grease as the lubricant.

 

Even the best mills of 19-ought-whatever can't match todays CNC milling.   They couldn't make a 'transmission,' as it were, that could handle the forces at work at the speeds needed.

 

Grease isn't the best lubricant, either.   Enclosed drives, with thinner oil lubricants, are needed for higher-speed running.

[Zomboid]

Don't the logging locos have offset boilers to make space for the engine section? Not having longwise symmetry like that isn't going to help the weight distribution; I imagine they got away with it on the logging lines because speeds and associated test forces were low.

 

so the engine part would probably need to be mounted in the same place as on a Stephenson pattern loco, in which case there would need to be a compelling advantage to a gearbox transmission compared to a simple bar to a cranked axle arrangement.