Imaginary Locomotives

[Mike 84C]

The ones bought by the GSR & MGWR in Ireland were an absolute bargain. Bought at an average price of £2200 for 26 locos as kits of parts. £1800 was allowed by Inchicore for erection and finishing. The boilers alone cost an average of £3375 in 1921.

[The Johnster]

Rode behind one Rosslare-Waterford in 1961, when I was 9, part of family holiday involving crossing from Fishguard on the 'St David' but the car being sent over on the 'cattle boat' to Waterford.  It got there about 3 hours after we did.  From what I remember of the journey, the Woolwich, sparkling in green CIE flying snail livery, was a lively little performer with a 6-coach train.

[Mike 84C]

That must have been the last one then 376. I have models of 3 of them 2 green ones and a lined black 388.

[Northroader]

Mind, Woolwich Arsenal was good at guns, but not locos. I gather the kits were found to need quite a lot of extra work before they could be put into traffic.

Similar thing happened after WW2, let’s keep Barrow in Furness shipyard mateys gainfully employed building Diesel engines under licence. On BR with Sulzer engines, a Winterthur Diesel was a very different creation to a Vickers Armstrong one, particularly welding.

[Mike 84C]

Reading "Locomotives of the GSR"  much of the work involved was conversion from 4-8 1/2" to 5-3". 

As regards Sulzer diesels I remember them as being pretty reliable it was the cooling systems that let them down. But I was only a traction trainee and not party to the invisible faults of their innards.  Were they not designed as submarine prime mover? that would be an easy life compared to a Brush type 4. Tick over to full power in a few hundred yds on acceleration then full power to tick over when coasting. Horses for courses?

[Northmoor]

56 minutes ago, Mike 84C said:

Reading "Locomotives of the GSR"  much of the work involved was conversion from 4-8 1/2" to 5-3". 

As regards Sulzer diesels I remember them as being pretty reliable it was the cooling systems that let them down. But I was only a traction trainee and not party to the invisible faults of their innards.  Were they not designed as submarine prime mover? that would be an easy life compared to a Brush type 4. Tick over to full power in a few hundred yds on acceleration then full power to tick over when coasting. Horses for courses?

It is generally accepted that rail applications are the most stressful duty cycle for a diesel engine.  It is probably one contributing factor to why the Class 159 DMUs from Salisbury depot are so reliable; they pull out of Waterloo then pull steadily up to cruise speed which they hold until at least Woking and often Basingstoke.  Compare with Pacers which often had to stop and start every 3-4 miles on many of their duties, that's hard on engines and transmissions.

[Compound2632]

23 minutes ago, Northmoor said:

Compare with Pacers which often had to stop and start every 3-4 miles on many of their duties, that's hard on engines and transmissions.

 

But they were buses and that's what buses are designed to do...

[tythatguy1312]

2 hours ago, Compound2632 said:

 

But they were buses and that's what buses are designed to do...

yeah but Buses are typically meant to last ~20 years in active service, compared to the 35 years that the Pacers achieved. That can't have been light on them.

Edited November 20, 2021 by tythatguy1312

[The Johnster]

Yeah but no but yeah but buses ride on pneumatice tyred wheels so their engines end equipment don't suffer the sort of battering that the railway equivalents do.

[5944]

13 hours ago, Northmoor said:

It is generally accepted that rail applications are the most stressful duty cycle for a diesel engine.  It is probably one contributing factor to why the Class 159 DMUs from Salisbury depot are so reliable; they pull out of Waterloo then pull steadily up to cruise speed which they hold until at least Woking and often Basingstoke.  Compare with Pacers which often had to stop and start every 3-4 miles on many of their duties, that's hard on engines and transmissions.

The diagramming wasn't particularly intensive either, which helped immensely. Salisbury depot would be full between the peaks, then First Group took over. I understand reliability is nothing compared to how it used to be under SWT. 

[Ben Alder]

Two LMS might have beens on their final trials - a 2-6-2 for lighter lines, a la Tom Coleman's plans, and a variant on the proposed Class Four with Ivatt tinkerings applied.

 

 

[Traintresta]

11 hours ago, Ben Alder said:

Two LMS might have beens on their final trials - a 2-6-2 for lighter lines, a la Tom Coleman's plans, and a variant on the proposed Class Four with Ivatt tinkerings applied.

 

 

I'm not sure the firebox on the 2-6-2 is in proportion to the boiler, it looks very undersized.

 

I'm curious to know more about the class 4 however.  I was aware of an LMS proposal for a small 4-6-0 for a Scottish line but I think that was meant to be a class 2.

[whart57]

1 hour ago, Traintresta said:

I'm not sure the firebox on the 2-6-2 is in proportion to the boiler, it looks very undersized.

 

 

It looks like the rear driving axle goes through the fire grate too

[Corbs]

12 hours ago, Ben Alder said:

Two LMS might have beens on their final trials - a 2-6-2 for lighter lines, a la Tom Coleman's plans, and a variant on the proposed Class Four with Ivatt tinkerings applied.

 

 

 

I especially like the Ivatt-ised Stanier 4MT!

[Flying Pig]

12 minutes ago, whart57 said:

 

It looks like the rear driving axle goes through the fire grate too

 

It doesn't - the firebox is wide and behind the rear drivers as on a Pacific, but a bit short because of the wheelbase of the chassis the model is based on.

 

@Ben Alder have you tried the model on a Fairburn tank chassis?  I reckon that would give you 4-5mm extra behind the drivers, but now I come to think of it, I don't know whether it would fit otherwise without major hacking.

[whart57]

20 minutes ago, Flying Pig said:

 

It doesn't - the firebox is wide and behind the rear drivers as on a Pacific, but a bit short because of the wheelbase of the chassis the model is based on.

 

 

That's what I mean. The fact the firebox is much shorter below the footplate than it is above is what makes it look as if the rear axle goes through the ashpan.

 

I'm inclined to say that this interesting attempt at a new class of loco demonstrates why 2-6-2 is a rare wheel arrangement for a tender locomotive. (Tank engines are different because you need to provide support to the coal bunker and prevent the end swinging out too much)

Edited November 23, 2021 by whart57

[AlfaZagato]

Tendered 2-6-2 'Prairies' were only rare in the UK.   They were fairly common in the US around turn of the century.   They lasted forever here, too.   Looks like Russia & the USSR both favored the type for passenger work.

[Flying Pig]

2 hours ago, whart57 said:

That's what I mean. The fact the firebox is much shorter below the footplate than it is above is what makes it look as if the rear axle goes through the ashpan.

 

 

All the LMS wide fireboxes were like that to some extent.  The extended upper section contained a combustion chamber and the ashpan was restricted to the bit under the wide grate between the frames of the rear truck.

 

I guess the reason 2-6-2 locos were scarce in the UK is that it was mostly thought that cheaper narrow-firebox 4-6-0s would do the work adequately and anything bigger was built as a Pacific.  I can't find an online reference to Coleman's ideas but I would expect they were related to the advantages of a wide firebox as coal quality deteriorated during and after WW2.  That makes sense and it's an interesting avenue to follow with might-have-been designs.  It isn't fundamentally any harder to arrange the firebox of a 2-6-2 than a Pacific and Gresley managed quite a small one in the V4.

[PhilJ W]

There was an intention to build more V2's but Thompson finished them off as pacifics. In the circumstances one of his better decisions.

[whart57]

45 minutes ago, AlfaZagato said:

Tendered 2-6-2 'Prairies' were only rare in the UK.   They were fairly common in the US around turn of the century.   They lasted forever here, too.   Looks like Russia & the USSR both favored the type for passenger work.

 

In terms of running qualities the 2-6-2 arrangement has a lot going for it, but the problem will always be fitting the axles round the firebox and grate area. Probably the more generous loading gauge of the US and Russia helped with that.

[Compound2632]

Is the rather "stretched" look of the 2-6-2 down to it having the classic Derby 8'0" + 8'6" coupled wheelbase? In modelling terms, is the mechanism off a Bachmann Stanier mogul?

[AlfaZagato]

2 hours ago, whart57 said:

 

In terms of running qualities the 2-6-2 arrangement has a lot going for it, but the problem will always be fitting the axles round the firebox and grate area. Probably the more generous loading gauge of the US and Russia helped with that.

Then what of Pacifics?  Same issues present there, yet they're one of the most common types worldwide.

 

I do know that one issue with Prairies  is that they like to hunt a bit, having a nominally balanced wheelbase.   Especially if the center was driven, as was common.

[62613]

39 minutes ago, AlfaZagato said:

Then what of Pacifics?  Same issues present there, yet they're one of the most common types worldwide.

 

I do know that one issue with Prairies  is that they like to hunt a bit, having a nominally balanced wheelbase.   Especially if the center was driven, as was common.

Would the issue with hunting be due to the position of the pivot for the leading truck, i.e., a bit further back on the chassis? A bogie pivot is going to be a bit further towards the front of the chassis, so may steady things a bit

[Compound2632]

14 minutes ago, 62613 said:

Would the issue with hunting be due to the position of the pivot for the leading truck, i.e., a bit further back on the chassis? A bogie pivot is going to be a bit further towards the front of the chassis, so may steady things a bit

 

But that should be compensated for by the transverse springing of the truck; in either case it should be leading the engine into the curve.

[whart57]

56 minutes ago, AlfaZagato said:

Then what of Pacifics?  Same issues present there, yet they're one of the most common types worldwide.

 

 

At a guess I would say that as a Pacific has a bogie on the front end it can move the rear pony truck back a bit and create more space for the fire grate without unbalancing the locomotive