Imaginary Locomotives

[Satan's Goldfish]

Looks alright added to a train. Not going to win any points for speed, but would probably be fun to be behind. Still waiting for the 'why it won't work' dissection though so I can go back and have to redesign it

 

[JimC]

A Castle or even a King boiler might be worthwhile with all that extra adhesion... Maybe a pony truck to help the leading unit into curves. Could be a better option than the proposed 2-10-2 for the iron ore traffic.

Edited March 2, 2018 by JimC

[Satan's Goldfish]

A Castle or even a King boiler might be worthwhile with all that extra adhesion... Maybe a pony truck to help the leading unit into curves. Could be a better option than the proposed 2-10-2 for the iron ore traffic.

I'm probably about to make a comment that will upset all the proper GWR fans, and shows my lack of knowledge on GWR at the same time; I thought all their 4-6-0s were pretty much the same (they look it!). Do Kings and Castles have bigger boilers then? I was aiming for something of a theoretical 1905ish vintage (hence Saint, small Prairie, and TGB tender), could a king/castle boilered version be its potential 1930s version maybe?

[Corbs]

Kings have bigger boilers but smaller wheels than Castles, so that they fit under bridges.

[Regularity]

Looks alright added to a train. Not going to win any points for speed, but would probably be fun to be behind. Still waiting for the 'why it won't work' dissection though so I can go back and have to redesign it

Dunno about “why it won’t work”, but it ain’t gonna win points for looks, either - although it would probably beat the Kruger, but most things would.

Kings have bigger boilers but smaller wheels than Castles, so that they fit under bridges.

Who wants to build a castle under a bridge?

[runs as required]

A 1905ish true compound Mallet would suggest that Churchward had been thoroughly convinced by the efficiencies of his French de Glehn compound Atlantic purchases.

As someone suggests, it might have been good for short heavy haul work - perhaps as a Mallet tank.

[28XX]

You have shown the protrusion of inside cylinders and outside cylinders as well, so the front truck is a 4cyl! This could be an inside 2cyl truck, which would help on curves, and be the high pressure, small volume truck. The front buffer beam needs to be attached to the truck, not the boiler too.

Edited March 2, 2018 by 28XX

[28XX]

Kings have bigger boilers but smaller wheels than Castles, so that they fit under bridges.

Nowadays you have to chop down the cab, safety valve bonnet and chimney too. Looks awful

[28XX]

Outside valve gear for the rear truck. No space for the ashpan otherwise.

[Satan's Goldfish]

I did wonder if there were too many rods there for it to have just been an outside cylinder truck... ok, so redesign to make just the boiler 'slide' on the front truck rather than having the frame solid to the buffer beam and the truck swinging underneath, and attach buffers to front truck. Noted, give me a few weeks It should fit the chassis better as a Mallet tank, the bunker helps use up some length, I just messed up my previous mallet tank by using a lengthened small prairie boiler rather than a proper big boiler. Might give that another go too.

[sir douglas]

and what usually happened was that bothe units were outside valve gear so both sets arew the same for standardisation of parts and ease of maintenance 

[Satan's Goldfish]

Same reason the front Low pressure cylinders will remain on the outside... the reason isn't that it's too awkward to hack around a picture of Lima tank chassis to make it look different honest

[Corbs]

This was the problem I always came up against when trying to do 'big four' garratts and similar. The technical requirements of the design nibble away at the 'donors' so much that they all end up looking the same and not like they came from any particular railway company.

[JimC]

Kings have bigger boilers but smaller wheels than Castles, so that they fit under bridges.

I know that's said, but I don't find it convincing. The Bear had the same diameter boiler as the King and 6ft 8.5in drivers. I think it more likely that Collett was simply continuing the trend in driving wheel size reduction seen since the 19thC.

 

I did a short study of GWR boilers here.

 

http://www.devboats.co.uk/gwdrawings/gwrstandardboilers.php

 

Basically

Saint, Star, Hall and Grange all have the same Standard 1 boiler.

The Great Bear had a bigger boiler all round, with a wide firebox, but it was too long in the barrel.

The 4700 2-8-0 had a boiler (Std 7) with the same diameters as the Bear, but a shorter barrel and narrow firebox.

The original concept for the Castle was a Star with a 4700 boiler, but the weight was too much, so in the end it was a 4700 firebox and a barrel intermediate between the 47 and a standard 1.

The King boiler was pretty much a 4700 boiler with a longer barrel and longer firebox. 

The Manor boiler was new, and smaller all round than the Std 1

[Satan's Goldfish]

Front changed so buffers move with front truck, and front cylinders have a slightly increased diameter. Supporting the boiler like that also helps make it look like it's putting more weight on the front too. It would always be possible to steal slightly from the triplex layout if the low pressure outside cylinders are too big; have cylinders the same size as the high pressure cylinders, but have twice as many, so the front truck could have 4 cylinders all of the same specifications (2x inside, 2x outside). Looks like there is bigger boilers of the correct vintage (thanks for that informative piece Jim), but i'll stick with drawing the Std 1 for ease.

[JimC]

One can imagine Holcroft suggesting that 3 low pressure cylinders at the front with his conjugated valve gear was the way to go. With inside Stephensons gear the levers for the conjugation ought to be nice and short, and the arrangement much more robust than the Gresley setup. If you assume divided drive, however, that forces the middle cylinder further forward and perhaps makes a pony truck essential. Otherwise the middle cylinder has to be inclined. As if three cylinders were used that would preclude the standard back to back cylinder castings, Churchward might have been persuaded to accept having all 3 cylnders inclined at the front.

Edited March 2, 2018 by JimC

[Satan's Goldfish]

This was a rush creation so doesn't look quite right. 2 shades of green doesn't help. Mallet tank using Std 1 boiler, on the 'commonality of parts' front, the boiler is positioned the same as with the tender version of the Mallet, meaning it's gained a trailing axle to support the extended bunker. 'GWR' needs to be more towards the front I think.

[Joseph_Pestell]

This was a rush creation so doesn't look quite right. 2 shades of green doesn't help. Mallet tank using Std 1 boiler, on the 'commonality of parts' front, the boiler is positioned the same as with the tender version of the Mallet, meaning it's gained a trailing axle to support the extended bunker. 'GWR' needs to be more towards the front I think.

 

I think that might look rather better as a 2-6-6-0T.

Edited March 2, 2018 by Joseph_Pestell

[Joseph_Pestell]

Kings have bigger boilers but smaller wheels than Castles, so that they fit under bridges.

I was on a steam excursion once when KGV disproved your theory. Somewhere near Wrexham as I recall.

[Satan's Goldfish]

I think that might look rather better as a 2-6-6-0T.

I've been debating in my head on the drive home whether to try and make (the tender version) a 2-6-6-0, with angled inside cylinders at the front to justify the extra length in front of the boiler, and the extra pair of wheels to support some of the weight and guide it into corners. The down side is it might make the wheel base to long to be sensible, whereas at the moment It's shorter than a Pacific. This would then make the tank a 2-6-6-2 which would look good.

 

Edit: nope, pony truck at the front is just going to add too much length, angled cylinders can just be supported by the existing front truck. I think adding these and other gubbins to the front in front of the smoke box will help balance the appearance a little, especially on the tank (along with putting the GWR logo in the correct place).

Edited March 2, 2018 by Satan's Goldfish

[Compound2632]

I'm mystified by Mallets and Garratts in general - the long path between the boiler and cylinders, between cylinders (in a compound Mallet), and the exhaust ought surely have been a disaster for thermal efficiency? But I must have missed something as they were evidently successful. What's going on? 

[relaxinghobby]

Insulate the steam supply pipes?

[The Johnster]

Dunno about “why it won’t work”, but it ain’t gonna win points for looks, either - although it would probably beat the Kruger, but most things would.

Who wants to build a castle under a bridge?

 

A troll who needs a defended base.

[Regularity]

A troll who needs a defended base.

Mmm. That was a bit gruff!

Edited March 2, 2018 by Regularity

[brack]

I'm mystified by Mallets and Garratts in general - the long path between the boiler and cylinders, between cylinders (in a compound Mallet), and the exhaust ought surely have been a disaster for thermal efficiency? But I must have missed something as they were evidently successful. What's going on?

But that might be mitigated somewhat by true mallets being compounds (so higher efficiency) and a garratts boiler having optimal proportions for steam raising (short and fat) a simple expansion articulated, as beloved by the big US roads has the disadvantage of a long skinny boiler so little heat gets to the front end, long steampipes big throw over on curves and mechanical complexity, but the ability to make something that was flexible, could pull the load of two locos and only needed one crew presumably outweighed that.

 

Re. Garratts designs and not fitting a railway's style, if you wanted a good garratt you'd be better off just telling beyer, peacock what you needed it to pull and let them do their job. The more involvement of the customer in the design process, the worse the result. B-P knew what they were doing, but others (Gresley, derby) insisted on introducing their own stuff to the designs which was unnecessary and made the finished locos less than they could've been.

A 262-262 garratt for the heavy coal traffic might not be a bad shout. You could easily get 50000lb te with a 16t axle limit for yellow route availability, same wheel size as a 45xx.