Lima/Bachmann 94xx conversion.

[The Johnster]

As a slight aside, the wheelbase has everything to do with a 6-wheeled locomotive, which has inside cylinders. The outside cylindered flavour can incorporate different design parameters.

 

As we've spoken earlier, the rotational sizes of the locomotive valve gear dictates the gap between the centre drivers, and rear drivers. Regardless of railway company, I'd guess that the difference between the basic design principles is less than 1/4". That's across the entire UK steam locomotive fleet. For every increase in cylinder stroke, you need to double the gap between centre & rear wheels. This has a detrimental effect on operability of the locomotive, as longer the wheelbase, the greater the radius required to get around corners. Also in this gap, just behind the centre drivers, is the motion bracket. This sometimes unseen part is vital to the safe operation of the steam locomotive. Its job is to take up the thrust from the loco pistons, and are the first part in turning steam energy from a fore-aft motion, to a rotational motion. As you can see, the  space betwixt  centre driver & rear driver is incredibly tight. This is well known as the danger area when oiling a locomotive; there's no real space for a human being and a set of motion gear. Some locomotive designs can incorporate a longer rear wheelbase, but this design puts the rear drivers in under the ashpan, which is not always the best design practice. The Hunslet 18" austerity has this, and can suffer from problems with keeping the ashpan clean. The Midland 0-6-0 also suffers with this.

 

So, Stephensons have a lot to answer for!

 

Chers,

ian.   

 

And much to be grateful for as well.  

[The Johnster]

I agree, a very significant part of the reason 200 of these locos were built under BR's order was to continue the long standing GW program of replacing the older South Wales absorbed/constituent engines. the likes of the TVR 04s.  They were also considered a development of the 'standard' 8750 pannier, and construction of panniers after 9682 was of 94xx.  They were certainly common in South Wales where they were allocated to replace older locos, but not unique to the area.  The 'standard' South Wales replacement had been the 56xx for the larger engines and 57xx/8750 for the rest, but Hawksworth reckoned he could improve on the 8750.  He did, in terms of power output, recognised by BR as 3F for the 8750s and 4F for the 94xx, including the lower boiler pressure 'production' BR locos.  The Canton drivers I spoke to in the 70s didn't rate them much though; they reckoned that an 8750 could do any job a 94xx was allocated to, rode better, and was easier to fire with a roomier cab.  Visibility through the cab front windows was better on the older engines as well; range on full tanks and bunker was about the same, so, the men reasoned, what was the point?  The very short working lives of these engines sort of bore this out.

 

The story about modern looking engines has some basis in fact, though, in regard to the Paddington ecs workings.  Somebody with some political clout had apparently complained about the antiquated appearance of the 8750s, with their Victorian looking domes, which spent long periods visible to the chattering classes from the lawn at Paddington.  15xx panniers, despite their chronic unsuitability for the job, were drafted in for the same reason; they are dock shunters based on the USATC yard switchers and very unsteady at more than the lowest speed.  The antediluvian M7s at Waterloo seem not to have caused such offence...

 

The truth is that the construction of Victorian 0-6-0s after WW2 was a wasteful nonsense; the putative 0-8-0 pannier would have been better for South Wales work.  

[The Johnster]

I think that's a bit of an urban myth as they were still building 8750s at the same time.

 

It was more the fact they were built to replace all the antiquated or non standard South Wales 0-6-2Ts many of which already had a similar boiler.

 

 

 

Jason

 

Not quite; the last 8750, 6779, a 6750 steam reverse shunting variant with no vacuum brakes, was turned out from Swindon in 1950 as the completion of a GW order, and the BR 'production series' 9410 and onwards were built by contractors after this starting in 1950.  AFAIK 6779 was in service before 9410, though the building periods must have overlapped.  9410 was built by Stephenson's, not at Swindon.

Edited June 18, 2018 by The Johnster

[The Johnster]

I think that's a bit of an urban myth as they were still building 8750s at the same time.

 

It was more the fact they were built to replace all the antiquated or non standard South Wales 0-6-2Ts many of which already had a similar boiler.

 

 

 

Jason

 

Not quite; the last 8750, 6779, a 6750 steam reverse shunting variant with no vacuum brakes, was turned out from Swindon in 1950 as the completion of a GW order, and the BR 'production series' 9410 and onwards were built by contractors after this starting in 1950.  AFAIK 6779 was in service before 9410, though the building periods must have overlapped.

[Dunsignalling]

I agree, a very significant part of the reason 200 of these locos were built under BR's order was to continue the long standing GW program of replacing the older South Wales absorbed/constituent engines. the likes of the TVR 04s.  They were also considered a development of the 'standard' 8750 pannier, and construction of panniers after 9682 was of 94xx.  They were certainly common in South Wales where they were allocated to replace older locos, but not unique to the area.  The 'standard' South Wales replacement had been the 56xx for the larger engines and 57xx/8750 for the rest, but Hawksworth reckoned he could improve on the 8750.  He did, in terms of power output, recognised by BR as 3F for the 8750s and 4F for the 94xx, including the lower boiler pressure 'production' BR locos.  The Canton drivers I spoke to in the 70s didn't rate them much though; they reckoned that an 8750 could do any job a 94xx was allocated to, rode better, and was easier to fire with a roomier cab.  Visibility through the cab front windows was better on the older engines as well; range on full tanks and bunker was about the same, so, the men reasoned, what was the point?  The very short working lives of these engines sort of bore this out.

 

The story about modern looking engines has some basis in fact, though, in regard to the Paddington ecs workings.  Somebody with some political clout had apparently complained about the antiquated appearance of the 8750s, with their Victorian looking domes, which spent long periods visible to the chattering classes from the lawn at Paddington.  15xx panniers, despite their chronic unsuitability for the job, were drafted in for the same reason; they are dock shunters based on the USATC yard switchers and very unsteady at more than the lowest speed.  The antediluvian M7s at Waterloo seem not to have caused such offence...

 

The truth is that the construction of Victorian 0-6-0s after WW2 was a wasteful nonsense; the putative 0-8-0 pannier would have been better for South Wales work.  

Presumably the rapid spread of diesel shunters on the WR meant there was no work left that was really suited to the 15xx, but it would have been too embarrassing to scrap such new locos.

 

Paddington carriage shunting was a job where their inappropriateness for anything that couldn't be done better by a diesel didn't impinge too much on the task in hand, and using them released an equivalent number of the more versatile 94xx to be more usefully employed elsewhere.

 

John

Edited June 18, 2018 by Dunsignalling

[The Johnster]

Pretty much, John; the 15xx were originally concentrated on the bigger ports, Avonmouth and South Wales particularly Newport but Cardiff and Swansea had them as well (not Barry AFAIK).  350hp diesel electric shunters, about the same weight on the same wheelbase, appeared at Severn Tunnel Junction for hump shunting in 1955, and were deployed on Cardiff docks by 1958; I do not now remember when they first appeared at Newport or Swansea but it was not very long afterwards.

[The Johnster]

Part the third, in which Johnster realises he's been worrying too much about the smokebox, and more plastic goes to landfill...

 

When we left the last instalment of this thrilling saga (or is it a sagging thriller), I was going to have to complete my removal of the inside part of the smokebox by hand and probably rather awkwardly, as the minidrill cannot be inserted all the way to finishing the cuts, but those of you who have already done this conversion will realise that I didn't need to do this in the event; the smokebox is a separate part which can be taken off the rest of the main body moulding, meaning that access with a power tool is quite easy.  The job was done earlier this evening in less than 5 minutes, and the smokebox barrel re-attached, with poly cement as the removal of material meant that the fit, if left unglued, left the thing drooping a little downwards towards the front (at my age I'm in no position to be judgemental about this), which opened a gap between the front of the boiler and the smokebox.

 

I have decided to leave the repaint until the new chassis is fitted and the loco is in one single piece, in order to ensure an even finish over both body sections.  I will be painting over the copper cap on the chimney; the existing attempt at copper seems far too bright and gold like to my eyes, and as the centre of the the chimney is solid which is highlighted by the 'gold' paint, I will be drilling a big 'ole down there as well.  The ultimate finish is to be fairly heavily weathered, so some very muted 'gold' copper may be visible, as will the brass finish on the safety valve cover.  I am not happy with the latter, which, while being a good shape, has no detail in the top of it, but I am not sure what if anything I can do about it beyond cutting the whole thing off and replacing it with a retrofit detail part if anyone makes one.

 

I posed the loco on it's old chassis for a 'before' photo to go with an 'after' shot in the same location when I've finished the job, but have now binned the old chassis; I cannot think of any practical use for it, and keeping it will just distract me into a futile attempt to try to find one.  It has no redeeming features; coarse wheels with no balance weights, visible plastic cog gear train, incorrect coupling rods, and no crankpins for the centre drivers, and there is no point in persisting with a chassis which has so many faults and does not run particularly well at any speed below about a scale 30mph anyway.  

 

That will be it for now until the new chassis turns up!  Thank you again everyone for your contributions and help!

Edited June 18, 2018 by The Johnster

[TheSignalEngineer]

For the safety valve I'm using the old Craftsman Models No.3 GWR Short type. I have just changed the chimney for their 2251 type. It seemed a little over-height when I test fitted, and from the drawing posted elsewhere by Miss Prism I think it was 1mm too tall. I drilled a hole down the middle, marked a line down one side, cut it in half with a hacksaw and glued the cut together using a bit of tube through it to keep it straight. Will try to post some progress photos later.

[34theletterbetweenB&D]

...Somebody with some political clout had apparently complained about the antiquated appearance of the 8750s, with their Victorian looking domes, which spent long periods visible to the chattering classes from the lawn at Paddington.  ....  The antediluvian M7s at Waterloo seem not to have caused such offence...

 Aethetics my dear. Swindon's frumpy Ann Widdecome, or Nine Elms delectable Honor Blackman?

[Horsetan]

......15xx panniers, despite their chronic unsuitability for the job, were drafted in for the same reason; they are dock shunters based on the USATC yard switchers and very unsteady at more than the lowest speed....

 

Unsteadiness doesn't seem to have affected the usefulness of the sole surviving one. 1501 has regularly hauled service trains in preservation, so we know the ride is acceptable up to 25mph.....

[timbowilts]

Unsteadiness doesn't seem to have affected the usefulness of the sole surviving one. 1501 has regularly hauled service trains in preservation, so we know the ride is acceptable up to 25mph.....

That depends on the crew’s definition of “acceptable” surely :^)

 

Tim T

[Horsetan]

That depends on the crew’s definition of “acceptable” surely :^)....

 

The engine seems to have had quite a few crews.

[Welchester]

 Aethetics my dear. Swindon's frumpy Ann Widdecome, or Nine Elms delectable Honor Blackman?

 

Swindon had better to offer than Ann Widdecombe; Diana Dors (née Fluck) was a Swindon girl and a Sunday School teacher. Invited back as guest of honour to open a church fête, she was introduced by the Vicar of St Mark's as 'Diana Clunt'.

[The Johnster]

I would have thought the rough end of Fochriw had better to offer than Ann Widecombe...

 

I always felt a bit of sorry for Diana Fluck/Dors, she seemed like a nice girl who had the misfortune to be a 'blonde bombshell', was turned into a 'success', and became a sort of parody of her manufactured and false persona.  Of course, she was not the only victim of this sort of thing.

[tomparryharry]

The 15xx, with its shorter wheelbase, has a somewhat rockier ride than its equivalent 94xx. I've driven both, and for all-out power, I'd hand it to the 15xx. However, it's far more liable to go 'rough' a lot sooner than either a 57 or 94xx. ISTR that Bridgnorth (SVR) always carries a spare set of main springs, just in case. In this day & age, any working steam loco is a credit to the people who look after it, regardless of area, lineage, etc.

 

Cheers,

 

Ian.

[TheSignalEngineer]

Here we are Johnster. Test fit of the Craftsman No,3 Safety Valve

 

 

and the modified 2251 chimney

 

 

The smokebox handrail has been fitted with better knobs and shortened at the sides

I have also started to cut away the cylinder cover at the front to make it look like the later version

[Fat Controller]

Swindon had better to offer than Ann Widdecombe; Diana Dors (née Fluck) was a Swindon girl and a Sunday School teacher. Invited back as guest of honour to open a church fête, she was introduced by the Vicar of St Mark's as 'Diana Clunt'.

IIRC, one of her family, Stan Fluck, was head of the Business Studies department at Bristol Poly in the early 1970s.

[Horsetan]

IIRC, one of her family, Stan Fluck, was head of the Business Studies department at Bristol Poly in the early 1970s.

OT, but any relation to the Fluck who, with Roger Law, created Spitting Image ?

Edited June 19, 2018 by Horsetan

[The Johnster]

Here we are Johnster. Test fit of the Craftsman No,3 Safety Valve

 

P6192314.JPG

 

and the modified 2251 chimney

 

P6192315.JPG

 

The smokebox handrail has been fitted with better knobs and shortened at the sides

I have also started to cut away the cylinder cover at the front to make it look like the later version

 

Just my opinion, but I reckon the safety valve cover looks too tall compared with photos of 94xx.  The 2251 chimney looks fine though.  It would make sense; the boiler is the same one as the 2251, mounted on similar frames.  I do not know offhand if the pitch is the same; it could be a little lower on the 94xx because of the smaller diameter driving wheels, but the 94xx is quite a 'tall' looking engine and I suspect it is the same, in which case the same size chimney could be used on both locos.

 

The cut out cylinder cover, showing the plate frames of a Hawkworth loco, are clearly worth doing.

[chris45lsw]

Just my opinion, but I reckon the safety valve cover looks too tall compared with photos of 94xx.  The 2251 chimney looks fine though.  It would make sense; the boiler is the same one as the 2251, mounted on similar frames.  I do not know offhand if the pitch is the same; it could be a little lower on the 94xx because of the smaller diameter driving wheels, but the 94xx is quite a 'tall' looking engine and I suspect it is the same, in which case the same size chimney could be used on both locos.

 

The cut out cylinder cover, showing the plate frames of a Hawkworth loco, are clearly worth doing.

The 9400 boiler pitch is 7' 9.75", 3.25" lower than the 2251 at 8ft 1", ie half the difference between the two wheel sizes.  Per the diagrams in Russell the chimneys and SVs seem the same. 

 

Chris KT

[TheSignalEngineer]

Just my opinion, but I reckon the safety valve cover looks too tall compared with photos of 94xx.  The 2251 chimney looks fine though.  It would make sense; the boiler is the same one as the 2251, mounted on similar frames.  I do not know offhand if the pitch is the same; it could be a little lower on the 94xx because of the smaller diameter driving wheels, but the 94xx is quite a 'tall' looking engine and I suspect it is the same, in which case the same size chimney could be used on both locos.

 

The cut out cylinder cover, showing the plate frames of a Hawkworth loco, are clearly worth doing.

The Craftsman safety valve is slightly out in several ways. It is about 0.5mm too high, the flare at the top is about 0.5mm too small and the flare at the bottom is also too small, the Lima base is probably better but it needs a new top. Taken together these faults accentuate each other in a photo. Before I finish I may try to get a better one.

[TheSignalEngineer]

The Craftsman safety valve is slightly out in several ways. It is about 0.5mm too high, the flare at the top is about 0.5mm too small and the flare at the bottom is also too small, the Lima base is probably better but it needs a new top. Taken together these faults accentuate each other in a photo. Before I finish I may try to get a better one.

On reflection I should have left the Lima safety valve  cover and just looked for a new top or a way of imrpoving it.. 

Edited June 20, 2018 by TheSignalEngineer

[The Johnster]

Well, you can console yourself with having prevented me from making the mistake.  My current thinking is to cut the top off mine and fit a new top, cut off from the one on the chassis donor 57x pannier which is on it's way; this loco will also donate it's buffers to the cause, possibly the entire buffer beams.  I don't have any plans to replace the Lima chimney at the moment, as it looks OK to me, but that may change if I see a better one on a trade stand at a show or something, especially if it's a turned copper example.  But I will be drilling a big hole in the top of the Lima chimney; I feel this will improve the draughting of the loco...

[Corbs]

Looks like I will soon have to follow suit and adapt a 57xx chassis to our 94xx. Originally I'd hoped to use a spare front/rear driver in the middle slot and drill out the rods to accept a bolt, but testing has been less than successful!

[DCB]

Unsteadiness doesn't seem to have affected the usefulness of the sole surviving one. 1501 has regularly hauled service trains in preservation, so we know the ride is acceptable up to 25mph.....

There are logs of 94XX running at almost 60 mph for many miles along the Thames Valley on 61XX diagrams, I don't think anyone would be daft enough to run a 15XX at anything like that speed.  The 15XX started as a 2-6-0.

 

The 9400 boiler pitch is 7' 9.75", 3.25" lower than the 2251 at 8ft 1", ie half the difference between the two wheel sizes.  Per the diagrams in Russell the chimneys and SVs seem the same. 

 

Chris KT

It's a pretty safe bet that the 94XX and 2251 cylinder blocks were identical.   The GWR generally took up differences in wheels size by moving buffers up or down the buffer beam, which is why the  2251 has that deep front buffer beam.