Imaginary Locomotives

[cheesysmith]

I was just reading anouther thread about 73s paired up on MGR trains, and it gave me a idea. What about if a run of modified class 73s, with a V8 engine from a 20 instead of the 4 cylinder version from the DEMUs. Then give it twin pantographs for operating off 1500v DC. I`m sure these would have replaced the Bo Bos on the woodhead, and might even have made it more efficient rather than changing locos at each end. I have a picture in my mind of a 73, with twin pantos, maybe a foot or two longer to fit in a bigger cooler group.

 

Anybody any good with a paint program, and want to replace the cooler group on a 73 with one off a 20?

[JimC]

These came about on another forum as a result of a discussion about Didcot's Barry wreck 5205/42xx

 

This was something I believe the GWR considered. Its basically a 5205 chassis given a Std 1 boiler and a tender. It would be very much equivalent to a 2800.

 

This one is completely fictional. Its the 4200 chassis truncated at the 3rd pair of drivers and retaining the Std 4 boiler. Its turned into what is effectively a small wheeled 4300 Mogul. The adhesion factor might be somewhat dubious, although the tractive effort would be no more than a Castle.

 

[The Johnster]

The 2-8-0 is unlikely to have ever been built; I see no advantage that it has over the 2884 except for a bigger tender, and the 3,500 gallon was found sufficient for a 28xx/2884's duties, so there is little to gain from making the loco pull a heavier one around.  I am not enough of a locomotive engineer to comment on what advantages drive on the second axle as opposed to the third might convey, or the reason for this difference between 28xx/2884 chassis and 42xx/5205/72xx chassis.  It may well have been a matter of axle spacing; I do not know if there is any difference without checking the drawings, but the 'set' of the firebox, especially the backhead, is a consideration in a tank loco and the GWR 8-coupled tanks did not have big cabs to start with; a tender gets around this problem but introduces problems for the crew running tender first!

 

The mogul looks like it would be a good banker, in which case the reason for it not being a prairie is probably due to axle loadings; perhaps somebody was thinking about running 16 coach expresses up Talerddig...  The small wheels mean it does not have much range for a tender loco, and the no.4 boiler is a way of making sure it can go a reasonable distance between firings.  Hemerdon?  Rattery?  Top speed would not have been high, probably 50mph or so, and the ride, um, interesting!

Edited February 25, 2018 by The Johnster

[Corbs]

How does one adapt a tender loco to be able to run tender first as well as a tank loco runs bunker first?

 

Is it a stability issue? Wear on the rear drivers? Danger of getting hit in the face by airborne coal?

Edited February 25, 2018 by Corbs

[34theletterbetweenB&D]

To the best of my knowledge this was never given much in the way of design attention in the UK. Larger tenders when half full of water could become very exciting (resonantly excited) indeed at high speed, with the loco going forward as intended...

[LNWR18901910]

These came about on another forum as a result of a discussion about Didcot's Barry wreck 5205/42xx

 

This was something I believe the GWR considered. Its basically a 5205 chassis given a Std 1 boiler and a tender. It would be very much equivalent to a 2800.

280-4200astender..jpg

 

This one is completely fictional. Its the 4200 chassis truncated at the 3rd pair of drivers and retaining the Std 4 boiler. Its turned into what is effectively a small wheeled 4300 Mogul. The adhesion factor might be somewhat dubious, although the tractive effort would be no more than a Castle.

 

260-small wheel-4200based.jpg

That's such a nice engine. I believe that should be worth an attempt in 00 model form.

[62613]

These came about on another forum as a result of a discussion about Didcot's Barry wreck 5205/42xx

 

This was something I believe the GWR considered. Its basically a 5205 chassis given a Std 1 boiler and a tender. It would be very much equivalent to a 2800.

280-4200astender..jpg

 

This one is completely fictional. Its the 4200 chassis truncated at the 3rd pair of drivers and retaining the Std 4 boiler. Its turned into what is effectively a small wheeled 4300 Mogul. The adhesion factor might be somewhat dubious, although the tractive effort would be no more than a Castle.

 

260-small wheel-4200based.jpg

Would the rear axle of the 2-6-0 be better moved further towards the rear of the chassis, to make room for the ashpan, and/or the driving axle moved forwards slightly?

[JimC]

I suppose you could consider the 2-8-0 and 2-6-0 as alternative answers to the question "what do we do with these 2-8-0Ts we don't need?" which in practice resulted in the 7200 2-8-2Ts. So in both cases they would be conversions, not brand new locomotives. I'm completely in agreement with Johnster when he suggests there would be at best no advantage over further 28s. The short spacing to the rear wheel of the 2-6-0 does look a bit odd: the wheel/firebox relationship is that of the parent 2-8-0T. As an even more bizarre answer to that question I schemed out a 2-8-0 tank/tender with the 42 basically unaltered other than the drag box, and a little short wheelbase 2,000 gallon tender added, assuming that a steam powered waterscoop could be managed. With the original short bunker of the first 42s I think the combination could even be turned on a 55ft turntable, but the full size 42/5205 bunker might be a bit marginal.

[Corbs]

One could theorise that more ROD 2-8-0s were bought post-war and fewer 28xx were built. The RODs were ready for scrapping when the 5205s were laid up...

[JimC]

I understand there was also a proposal to reboiler the RODs with Std 1 boilers. I may have to take a look at that.

[tomparryharry]

The 42xx and the 28xx do different jobs. The 42 is a short distance movement, the 28 for longer distances. you wouldn't normally see a 28 working 'up' the valleys, but you would see one 'across' the valleys from, say Neath to Pontypool Road, and the long jobs from Pontypool to the Birkenhead area, on the Jellicoe Specials'.

 

The 42xx was excellent iron ore haulage, especially from the midlands, like Banbury, down to South Wales. As we all know, the 72 came about because there was a surplus of class 8 haulage in south midlands/south Wales. The ROD came available because it was cheap! Remember that the GWR was a company, and it answered to its shareholders. The £100 locomotive had a lifespan to the point when it became uneconomic to repair. One of its advantage was  that the loco had a huge field of spares. If it had a working lifespan of only one year, then no problem. Take it apart. This only became a proper problem when a locomotive failed to fulfil its expected lifespan. You really don't need to change for a No1 boiler, when there are 50-odd repaired ones awaiting the call. The longevity of the ROD is down to its sturdiness, and a vast spares base.

 

The 28xx appears to be a bit faster. Haulage across the classes seems about the same. Certain jobs on the diagram couldn't be used, as the relatively lower speed meant longer times between block sections. Some night time jobs were specifically meant to be ROD turns, whilst the balancing day turn would be a 28xx.

 

Horses for courses. The big railway was a common carrier by law. That's probably why you see so many different classes, doing vaguely similar jobs.

 

Cheers,

 

Ian.

[Corbs]

The 42xx and the 28xx do different jobs. The 42 is a short distance movement, the 28 for longer distances. you wouldn't normally see a 28 working 'up' the valleys, but you would see one 'across' the valleys from, say Neath to Pontypool Road, and the long jobs from Pontypool to the Birkenhead area, on the Jellicoe Specials'.

 

The 42xx was excellent iron ore haulage, especially from the midlands, like Banbury, down to South Wales. As we all know, the 72 came about because there was a surplus of class 8 haulage in south midlands/south Wales. The ROD came available because it was cheap! Remember that the GWR was a company, and it answered to its shareholders. The £100 locomotive had a lifespan to the point when it became uneconomic to repair. One of its advantage was  that the loco had a huge field of spares. If it had a working lifespan of only one year, then no problem. Take it apart. This only became a proper problem when a locomotive failed to fulfil its expected lifespan. You really don't need to change for a No1 boiler, when there are 50-odd repaired ones awaiting the call. The longevity of the ROD is down to its sturdiness, and a vast spares base.

 

The 28xx appears to be a bit faster. Haulage across the classes seems about the same. Certain jobs on the diagram couldn't be used, as the relatively lower speed meant longer times between block sections. Some night time jobs were specifically meant to be ROD turns, whilst the balancing day turn would be a 28xx.

 

Horses for courses. The big railway was a common carrier by law. That's probably why you see so many different classes, doing vaguely similar jobs.

 

Cheers,

 

Ian.

 

I'm not really sure what you're explaining.

Isn't that the difference between a tank and a tender loco?

2800 and 4200

Same cylinder sizes, same driving wheel sizes. Different boiler pressure.

So plonking a Std. 1 boiler on 5205 chassis and ditching the tanks/bunker for a tender creates a similar loco to the 28xx, no?

 

The Great Western Railway bought 20 ROD locos in 1919.

 

I'm theorising that ROD and 2800 locos did the same kind of work, so perhaps had the ROD not asked for so much money (or whatever) then the GWR may have bought more in 1919, and (for example) not built the last batch of 2800s.

Thus when the ROD 2-8-0s were knackered is around the same time as there were a load of 4200s sitting around at Swindon doing nothing, so why not put them to some use (similar to a 2-8-0 version of 9351 on the west somerset railway)

or they may have built the 2884s earlier

 

or maybe they didn't bother buying the 2nd batch of RODs 

 

it's all imaginary anyway...

Edited February 26, 2018 by Corbs

[tomparryharry]

I'm not really sure what you're explaining.

Isn't that the difference between a tank and a tender loco?

2800 and 4200

Same cylinder sizes, same driving wheel sizes. Different boiler pressure.

So plonking a Std. 1 boiler on 5205 chassis and ditching the tanks/bunker for a tender creates a similar loco to the 28xx, no?

 

The Great Western Railway bought 20 ROD locos in 1919.

 

I'm theorising that ROD and 2800 locos did the same kind of work, so perhaps had the ROD not asked for so much money (or whatever) then the GWR may have bought more in 1919, and (for example) not built the last batch of 2800s.

Thus when the ROD 2-8-0s were knackered is around the same time as there were a load of 4200s sitting around at Swindon doing nothing, so why not put them to some use (similar to a 2-8-0 version of 9351 on the west somerset railway)

or they may have built the 2884s earlier

 

or maybe they didn't bother buying the 2nd batch of RODs 

 

it's all imaginary anyway...

Hi Corbs,

 

Sorry If I've not explained myself fully. A 42xx is far more suited to short distance work. It doesn't have a water scoop, and, more importantly, a limited water supply (1,800 gallons). The 28xx has a normal 3,500 gallons, and scoop. The ROD fares rather better, being 4,000 (4,250?) gallons). I guess you can alter the bits around, but I've never seen them. As I've said however, you probably wouldn't see a Swindon No1 boiler on the ROD. The Western bought 80-odd of them, which allowed a vast amount of spare parts.

 

The 42xx has extra jointing on the coupling rods, to allow more sideplay on the rods. I don't think I've see them on a 28xx, or an ROD. In the valley work, the42xx is more forgiving on the curved sections.

 

The ROD had a poor reputation on the Western (so I'm told) which was somewhat unjustified. 

 

 

 

Once again however, if the Western had a particular traffic requirement, then there's nothing to stop us seeing any particular type. Churchward is well known for instructing Harold Holcroft to "get me out a 2-6-0, and bring in all the standard parts you can."

 

History has (I think) been unfair on the poor old ROD. There were 521 built. If it wasn't right, you can bet they would have been rebuilt by other companies of the big 4. A good second-rank (some would say first rank) heavy freight locomotive.

 

Cheers,

 

Ian.

Edited February 26, 2018 by tomparryharry

[JimC]

History has (I think) been unfair on the poor old ROD. There were 521 built. If it wasn't right, you can bet they would have been rebuilt by other companies of the big 4.

 

LNER enthusiasts, how did the LNER crews regard them? From reading LNER.info the LNER seem to have tried quite a number of boiler variations on the class.

 

I know the GWR crews generally loathed them, but I'm not sure any other pre grouping freight locomotive would have come out well in a head to head with the 28s, The GWR reworked the ones they kept appreciably - they had new copper inner (at least) fireboxes and GWR superheaters. It would be interesting to know how different the new fireboxes were to the originals. 

 

The LMS didn't keep the ones they had very long - indeed weren't many bought simply as a supply of cheap tenders? Wikipedia (FWTIW) suggests they had poor route availability on the LMS though.

Edited February 26, 2018 by JimC

[brack]

The GWR ones they chose to keep (as opposed to work to death and then throw away) lasted until well into BR days. Just because Thompson chose to rebuild something doesn't necessarily mean it was a bad loco (and they were nearly 30 years old at that point), Looking at the stuff they produced themselves I don't think that LMS loco policy in the 20s is any guide to how good a design is. Those that went to Australia and China certainly lasted long enough. about 100 of them saw military service in WW2 as well - if they were awful, they'd have requisitioned something else. They lasted pretty well for a 1911 design - over 50 years of service. It isn't much of a surprise that they were surpassed by stuff 20 years later in design, but they were solid and dependable enough to select as the ROD loco in the first place and to keep them around for a half a century.

[The Johnster]

No doubt that the Robinson 2-8-0 was a rugged thing, and seems to have been grudgingly admired even by GWR loco crews for it's toughness, but there are important differences between it an a 28xx.  They locos are of a size and haulage capacity, and have similar sized driving wheels, but the 28xx were vacuum fitted, which the ROD (to use the GW vernacular) was not, and the 28xx were happy running at 50+mph, which the RODs were certainly not!  Their best work on both the Great Central and the GW was as heavy mineral haulers, a job which requires brute strength but nothing much else; speeds are 25mph or lower.  A 28xx must have been a nicer place to work than an ROD on similar work.  A 28xx, being vacuum fitted, will be used on part or fully fitted freight work which the ROD cannot handle; they will in consequence be regarded as faster locos.

 

It is a little like comparing an Austerity 2-8-0 to a Stanier 8F, the loco it was based on.  The 8F is more refined, rides much better, and is probably easier to fire, but the WD is designed to be cheaply and quickly built with readily available materials in a wartime economy.  Nobody liked them much, but like the 04s, they were tough and robust.

 

As Ian has pointed out, the coupling rods on 42xx/5205/72xx tanks were jointed in order to cope with sharp curves, I believe with the Western Valley route from Ebbw Jc to Ebbw Vale's iron ore trains in mind.  Even with this, the frames strained and the locos suffered from tank leakage, a problem on a loco with a barely sufficient water supply to start with.  As I said, I am not a loco engineer, and do not know if the 2nd axle drive of these engines is a consequence of the jointed coupling rods; perhaps someone of greater erudition in the matter will comment?

[34theletterbetweenB&D]

... how did the LNER crews regard them? ...

 The usual mixture. Ex-GCR folks regarded them as the standard against which all other heavy freight units should be judged, the GNR and NER guys knew their three cylinder heavies to be superior: which they were, in BR rating class 8 rather than class 7.

 

 ... the LNER seem to have tried quite a number of boiler variations on the class...

You can add the GCR to that. There was a larger boilered version, class 8M, later LNER O5, and experiments with special boilers with fireboxes adapted to 'colloidal fuel'.

 

Once the LNER had its hands on the GCR build supplemented by the purchased RODs, this was the de facto freight heavy for the system (and very welcome too as the RODs came at not too great a price). But! The design was flawed by the idiocy of the expensive Belpaire firebox: even if the fiction of its supposed advantages had been true, these were not required for a heavy freight unit's power demand. Doncaster had ample experience and confidence in the cheaper round top firebox boiler's capabilities, so naturally enough as the original boilers came up for renewal, these cheaper alternatives were fitted. There were effectively three rounds of this process as the most cost effective scheme to retain all re-useable parts in conjunction with a replacement boiler was devised.

 

What came to be appreciated was that the frame strength was good, and this justified yet further exploitation. As locos wore out, under Thompson those needing new cylinders and gear got a yet more extensive rebuild using parts standard with the B1, which resulted in the O1, a class 8 unit. The modern engine arrangements enabled these to run fast, famously ion the 'windcutters' on the GCR London Extension route. Locos with only the boiler needing replacement retained their original engines and got the same boiler as the O1, and were classed O4/8.

[JimC]

 As I said, I am not a loco engineer, and do not know if the 2nd axle drive of these engines is a consequence of the jointed coupling rods; perhaps someone of greater erudition in the matter will comment?

I'm not a loco engineer either, but hopefully I've absorbed some stuff spending a lot of time looking at their work while writing and drawing the book in the sig...

 

I believe the original plan for the big freight tank was a 2-8-2T much more closely based on the 28s with a Std 1 boiler (RCTS J38). Looking at the drawings here this would have been a long locomotive with an awful lot of throwover at the back, so its not surprising it wasn't progressed with. I just crudely blocked it out, and its a horror! The obvious next alternative was to put a Standard 4 boiler on, but when I line up a standard 4 boiler against the 28 chassis then the firebox comes smack against the third set of driving wheels, so that wasn't viable. 

 

So what it looks as if what they did was to move the second pair of driving wheels back to the same position as the  3150 2-6-2T, using the shorter size of con rods as per the 2-6-2T, and the third and 4th drivers further back yet so there was space for the firebox between the second and third drivers - basically the same arrangement as the 2-6-2T but with two driving wheels, not a driving wheel and a trailing axle. But this meant an undesirably long fixed wheelbase, hence a degree of flexibility from coupling rods and thin flanges on the centre driving wheels.

 

I could produce a drawing of the chassis and boilers all lined up against each other if folk are interested and it would help.

Edited February 27, 2018 by JimC

[The Johnster]

That makes sense, Ian.  A 2-8-2 tank with a no.1 boiler would have been very heavy as well, but the later 2-10-2 tank proposal with a King boiler shows that the basic idea was still floating around years later.  In the end the 2-8-0 tank series proved very good donkeys for South Wales and Cornish China Clay work, powerful and with good adhesion, heavy enough to be effective in braking loose coupled loads, and with an adequate range for short haul work.  The 72xx rebuilds proved their worth on long distance coal and iron ore work.  If they had a fault, it was the restricted space in the cabs, which made firing more difficult than it should have been, but the same could be said of the 56xx and many of the pre-grouping rebuilt 0-6-2Ts as well.

 

Swindon liked making locos out of standard Churchward parts, and the use of the large prairie/43xx connecting rod on the big goods tanks is a good example.  Collett deviated in terms of driving wheel sizes to some extent, and the Castle, King, and Manor boilers, but kept to the hymnsheet in most other respects.

[FPH 603]

Hi all,

 

Just wondering, is anyone good at making new 1st generation DMU cabs?

 

 

Technically this is a DEMU but I'm making this out of a DMU. Currently I have a Swindon Inter-City cab on it but I don't think this really suits a 57ft underframed suburban train. Previously I had a 104 styled cab but found this was too bland, and personally the Derby style cab is very generic amongst majority of the DMU fleet.

 

EDIT: Do DEMU's really need end mounted jumper cables or is this just Southern Region practice?

Edited February 27, 2018 by DoubleDeckInterurban

[Northmoor]

It is a little like comparing an Austerity 2-8-0 to a Stanier 8F, the loco it was based on.  The 8F is more refined, rides much better, and is probably easier to fire, but the WD is designed to be cheaply and quickly built with readily available materials in a wartime economy.  Nobody liked them much, but like the 04s, they were tough and robust.

I was looking at the latest Steam Railway mag in the WHSmith reference library today and coincidentally, there is an article about the foibles of the "Dub-dee", based on an interview with the workshop and loco crews experiences on the K&WVR.

[Mr_Tilt]

 

 

EDIT: Do DEMU's really need end mounted jumper cables or is this just Southern Region practice?

 

 

Depends if there's a need to operate them coupled together. If there is there has to be some means of passing the control signals through to the other half, and the jumpers do just that.

 

Think Class 50s, as they operated in pairs during their time on the WCML.

[FPH 603]

Depends if there's a need to operate them coupled together. If there is there has to be some means of passing the control signals through to the other half, and the jumpers do just that.

 

Think Class 50s, as they operated in pairs during their time on the WCML.

Well this would be a 'one off' unit and it wouldn't operate main line express trains, so I'd assume I wouldn't need them.

[LNWR18901910]

There is the Class 101 DMU which is the single railcar version that is Daisy's basis. Maybe BR could've made an experimental prototype and sold her to the NWR and Sir Topham Hatt?

[Satan's Goldfish]

Back to Mallets, I present the GWR mixed traffic tender version!

 

It was commented that the boiler on my previous version would have been too small (it used a stretched small prairie boiler), so this one is based on a Saint body mounted on 2 small Prairie drive sets (Just noticed I've forgotten to enlargen the front low pressure cylinders). The small Prairie was apparently good for 60 mph so it like to imagine this can achieve similar speed, hence it's MT status, but I doubt there's many passenger services that would really need something like this.

 

I could have stretched the boiler a bit but decided it would be better to leave it as an 'off the shelf' item, the only alterations are the removal of the splashers and slightly reshaping the cab as there's no longer a splasher cutting into it. The tender is a stretched standard Saint tender with The Great Bear style bogies, just because I like them.

 

I'm not sure the front is quite right, the buffer beam looks a bit close to cylinders that will be moving around curves. Again, I could have squished in the wheel spacing but decided to leave it as an 'off the shelf' part rather than creating a fresh design.