British 8 coupled loco's

But much more expensive, and post the great depression that really counted. It seems the class started off as "we've got more 42s than we need now, what can we do with them". A tender conversion - at least the one outlined by Swindon drawing office - would have involved a Std 1 boiler as well as a new tender. A much bigger deal than a frame extension, a radial axle and a new bunker.

 

They had too many 4200s and the Aberdare 2-6-0s were reaching the end of their life. If the fuel and water capacity of a tender loco was still needed I suppose a direct Aberdare replacement could easily have been made by just removing the trailing axle

 

I think that the intention was simply to remove the tanks & bunker & attach a tender

 

Another 8-couple tank engine design was the LSWR (Urie) G16. These are sometimes described as "a tank engine version of the S15", though since they had a different number of driving wheels, of a different diameter, with a different boiler design and no doubt completely different frame layout, that seems to be one of those glib phrases that doesn't actually mean very much. Anyway, they were designed for hump shunting, and were relatively rarely used on longer duties. An impressive-looking loco though, if your tastes run to the shipbuilding school of loco design.

Tom

 

You made me go and look it up, and even the H16 sister class of 4-6-2T locos doesn't have the same axle spacing as the S15, despite having the same cylinders and driver diameter.

On a similar note, one class I haven't seen mentioned is the GCR/LNER S1 0-8-4T. These were hump shunters built under Robinson for Wath yard initially in 1907, with a couple more built under Gresley with boosters (of course!) in 1930, two of the originals then going to Whitemoor. Like all dedicated hump shunters, they were quickly replaced by diesel shunters when they appeared on the scene, and appear to have been even less useful outside the confines of a dedicated large yard than a G16. The link doesn't mention it, but I'm sure I remember seeing that their nickname was the Wath Daisies, which amuses me for some reason...

 

I think whoever suggested that would have no idea of loco design. The distance between tender and firebox would mean the fireman carrying the coal. Mind you, the long armed GW fireman might just have coped.

 

I think it was part of a GWR training scheme - firemen were encouraged to grow their arms to greater length, such that by time they qualified as drivers, they could operate the brake while still being able to see out of the cab ...

Tom

 

That difference in axle spacing is useful to remember whenever the usual suspect brings up, roughly biannually, the prospect of using a redundant S15 as the basis for an H16 new build ... Not to mention a very different boiler design. There is a useful pair of general arrangement drawings in Bradley which show that the H16 and S15 had a completely different relationship between the front and back of the firebox, the slope of the grate, and the positions of the two rear driving axles. The H16 has a very gently sloping grate, and the front of the firebox is more or less over the middle axle, and the back is well in front of the trailing axle. On an S15, the grate slopes much more steeply downwards, with the front immediately behind the middle axle but the back of the firebox well behind the trailing axle, and the ashpan is shaped to clear the trailing axle. If you tried to make a 4-6-2T, or even a 4-6-4T version of an S15, you would essentially run out of length for any kind of realistic bunker: it works for the H16 because the boiler is shorter and therefore the cab starts further forward, with the bunker behind.

(I also wouldn't fancy trying to throw out the fire of an engine with a grate as long as an S15 from within the confines of a tank-engine cab: there would be insufficient space to manoeuvre the fire irons).

Tom

 

The Lancashire and Yorkshire Railway also had some 0-8-2 tanks for banking. I believe their nickname was Little Egberts. They are really obscure but I believe they were built for banking, perhaps on Copy Pit. Does anyone have more information?

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Yes, they did, the 1501 (1501-1505 Class and known, as said, as 'Little Egberts' after a troupe of circus elephants. There were only five of them, built March - April 1908, and the odd thing is that both intermediate wheelsets were flangeless. They were not tank versions of George Hughes' eight-coupled tender engines and they had little in common with them. All survived into LMS days but the last was withdrawn as 11803 (ex-1504) in October 1929.

https://uk.images.search.yahoo.com/...273d3cd5b4e33897f287d40fb93b.jpg&action=click

 

Thank you for the information

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Some might say there would be some practical difficulties...

 

I thought the Gas Works loco men had to built like gorillas to do their jobs, so they should be fine . . . . . . on second thoughts - you just need a very long smokebox and move the boiler back a bit, sorted ?!

 

Point taken

 

Nice illustration which does however illustrate how a neat direct replacement for the Aberdares could have been made, maybe with liners to reduce the cylinder bore to 18", if the rear axle was lost.

 

I think though that too would have been a much more substantial job, with all the braking and other gubbins needing to be changed. I believe that the 72s weren't even repainted, they just painted the new work. The nice thing about just welding a bit on the back is the minimal amount of design work required.
The adhesion would have been pretty ropy too, it would probably slip like a light Pacific unless (as you suggest) it was derated in one way or another.

Here are some sketches I did for my fictitious locos page of some increasingly silly ideas for how to use the 42s.

This was a Swindon proposal, noteworthy for the very high pitched boiler to get ashpan space.


This is my take on the "truncated as a 2-6-0"

And this is really silly.

 

A 2-6-0 weighted up to 19.5 tonnes per axle would probably only be about 2.5 tonnes short of the adhesive weight of a 4200 low on fuel and water. However in the end the 7200's water capacity of 2500 gallons allowed them to be used on long journey's at no real disadvantage against a tender loco.

 

Just need a diesel brake tender on the front and you have come full circle from early double tender locos ...

Being more serious: I assume you intend the tender as a water carrier (it would challenge the arms of even a GWR fireman if it had coal in it). Doing a bit of a fag packet calculation, and assuming Wiki is gospel for loco statistics:

42xx - 3.5 tons coal, water 1,800 gallons
5205 - 4 tons of coal, water 1,800 gallons
72xx - 6 t0ns of coal, water 2,400 gallons

Let's assume they used 50lb per mile of coal; evaporated 7lb of water for every 1lb of coal; and let's also assume that a prudent allowance was to leave at least 1/2 ton of coal left over from a duty before needing to replenish; and a prudent allowance for water was to leave 300 gallons in the tanks.

Plugging those numbers in gives:

For 42xx / 5205 types, water-limited range on one tank full (1,500 gallons)
= 15,000lb of water evaporated,
= 2,142lb coal burn
= 42 miles

For 72xx, water limited range on one tank full with prudent allowance (2,100 gallons)
= 59 miles

Coal-limited range on one bunker of coal, allowing for multiple water stops:

- 42xx = 135 miles
- 5205 = 155 miles
- 7200 = 245 miles

For a goods engine that is unlikely to be making really long non-stop runs, coal is the limiting factor, since replenishment requires going back to a loco shed; water can be picked up at most stations. So you can see the logic of just adding a larger bunker. (Presumably much beyond 6 tons of coal and you would start getting limited by ashpan capacity and smokebox capacity, requiring a trip back on shed anyway, so there is diminishing returns past that).

Worth noting as well that at a working average of say 20mph, 245 miles is already a 12 hour duty, beyond what a single crew could do in any case.

A tender engine version would suffer similar problems; you get a bit more water range at the expense of extra weight of a tender to drag round, but it is unlikely you would usefully carry more coal than they already managed to get into a 72xx.

Tom

 

On the Swedish narrow gauge (891 mm) they were popular. This is the Motala standard design, built in about 19 copies (with some variations) for a large number of different railway companies. About 8 more were built by other manufacturers (4 by Henschel at inflation sales prices after WWI). Lightweight design, with only 6 ton axle load. Very popular and versatile. Four are preserved, I think.

https://digitaltmuseum.org/021018123480/statens-jarnvagar-sj-np-3031

This is one of the preserved ones. Henschel built on the island of Gotland in the Baltic:
https://www.jarnvag.net/banguide/hesselby-roma

 

Wikipedia is indeed dubious. All the 2-8-0Ts ended up with the same coal capacity after frame extensions at the rear, while the 2-8-2s had two different bunker types with a different balance between coal and water (There was a water tank under the coal on all the larger types).