Imaginary Locomotives

[Ohmisterporter]

On 12/12/2023 at 12:44, burgundy said:

Have you ever wondered what the boiler and cab of a Billinton B2 would look like, if attached to the wheels and frames of a Gladstone, with an added leading bogie. The result is a rather elegant, inside cylindered Atlantic. 

In case your imagination is boggling, have a look at page 103 of LB&SCR Modellers' Digest, Issue 18 which is now on-line.

Best wishes 

Eric 

 

Eric, thanks for that link. I am not a modeller of the LBSCR but can easily see the attraction. Several hours spent reading this with many more to come I expect.

Geoff.

[burgundy]

12 hours ago, Ohmisterporter said:

 

Eric, thanks for that link. I am not a modeller of the LBSCR but can easily see the attraction. Several hours spent reading this with many more to come I expect.

Geoff.

Thank you. 

I would hope that much of the content would be of wider interest, either for the quality of the modelling or the ideas that are being explored. And the challenges of pre-grouping modelling are very similar, whichever company you follow.

This issue has given me particular satisfaction, with its range of authors and diversity of content.

Best wishes 

Eric 

[JimC]

I put this together after a thread on another forum. 
I've always considered that the chief issue with the Great Bear was excessively long fire tubes, but it was pointed out that there was at least one successful locomotive class with 23ft tubes - the German DRG05 4-6-4 that held the steam speed record with 200km/h on essentially level track. I took a look at the numbers, and basically if the Bear's firebox and grate were increased in size by about 25% the resulting proportions aren't so different from the DRG05. So here you are. 

Edited December 21, 2023 by JimC

[Deeps]

1 hour ago, JimC said:

I've always considered that the chief issue with the Great Bear was excessively long fire tubes

I no nothing about the shortcomings of the ‘Bear’ but every time I look at a picture of it the only fault I see is how short the cab is. It spoils the overall proportions of the beast and it would have created a relatively exposed environment for the crew. In the image above, which looks quite impressive, there is a considerable gap between the front of the firebox and the rear driving axle. If the firebox were shifted forwards as far as possible (I do not know if there might be other fittings in the way) it would provide a better space for the crew and improve the proportions.

[JimC]

52 minutes ago, Deeps said:

 If the firebox were shifted forwards as far as possible 

The firebox is six feet wide, so it must clear the whole wheel, not just the axle.

[Deeps]

18 minutes ago, JimC said:

The firebox is six feet wide, so it must clear the whole wheel, not just the axle.

That’s a shame. As I implied, I have limited knowledge of such things, other than GWR 4-6-0 fireboxes seem to fit between the drivers. As the boiler in question is of German design I can appreciate that the profile of the lower extremities are clearly different.

 

What you need is a Bulleid boiler (tongue in cheek)!

[DenysW]

5 hours ago, JimC said:

I've always considered that the chief issue with the Great Bear was excessively long fire tubes

I'd add that it was too heavy (in tons/axle) for any route except London-Bristol, and that the GWR was very reluctant to upgrade its large inventory of turning circles which maxed-out at 65'. I fear your rather elegant sketch is of an even heavier locomotive as well as even longer.

[rockershovel]

13 hours ago, JimC said:

The firebox is six feet wide, so it must clear the whole wheel, not just the axle.

Hence the late appearance of US locos with rear trailing trucks and extended combustion Chambers 

[JimC]

I've tidied up my sketch a bit and given it outside bearing for the trailing bogie, and the Bear's original 8 wheel tender. There seems to be an awful lot of daylight under the tender, which makes me wonder if I've misinterpreted the limited drawings I have. 

The six wheel tender version would have just about squeezed onto a 65ft turntable, albeit probably too out of balance to turn readily. This one on the other hand is just a fatal bit too long, although in practice a removable extension piece as was done with some 55ft turntables would be a viable option for both.

 

The Bear's tender is more interesting than I suspected when I came to draw it. It doesn't seem to have the well between the frames of the other standard tender so has higher sides. The tender in the other drawing is a well tank 3,500 gallon tender, but it's one of the ones that was given essentially cosmetic higher sides than it really needs.

Edited December 22, 2023 by JimC

[Mike 84C]

why not have a trapezoidal firebox as fitted to the Nord super Pacific's?

The front part fitting between the frames and the rear part above the frame for the wide firebox part, combustion chamber in the boiler and you may have a lighter Pacific sized loco.

 To me the Baltic does not "sit" so well as the Pacific arrangement  But a very interesting idea.

It may have been easier to fire than a Castle or King having a shorter wider firebox, less effort in firing to the front and just firing round the sides. Also better able to cope with poorer quality coal and less skilled firemen.

[DenysW]

I think we risk forgetting that the design is an integrated process where the optimum size* all of the parts is set by the target horsepower at the target speed. From an American book by William Withun, you divide the design horsepower by 30 for saturated and 36.9 for superheated to get the grate area. You can get the cylinder volume required from the design horsepower, the boiler pressure and whatever relationship you favour for the effective working pressure vs. piston speed. This gives you the mass of steam you need, at 55 lb/ft2/hr telling you the area of directly heated surface you need, with an allowance of 10 lb/ft2/hr for steam generated by the tubes.  The last number assumed 18 ft tubes, 2.25" diameter, with the actual tube size set by the water quality available.

 

The mass of steam sets the mass of coal at 6.75 lb-water per lb-coal for 14,000 BTU/lb bituminous coal, and that tells you whether hand-firing is sensibly achievable. The loading gauge sets the maximum outside cylinder diameter (21.5" in the UK according to Churchward), and therefore also sets the number of cylinders you need if you can't get by with two.

 

Then you pass the whole mess to a mechanical engineer to get a weight for that boiler and those mechanical parts at that pressure. 

 

So the 23' tubes is Churchward working on the smaller part of the steam-generating puzzle, but probably also the easier part to vary once the boiler diameter has reached the loading gauge or is near.

 

* Optimum: each element is developing the same hp/ton of metal.

[John Besley]

The cab still looks to short as the position of the reverser would mean the driver standing on the tender fall plate.

 

As for the poor fireman he'd have to do likewise to fire to give him the room to swing a shovel full the length of that box

[Niels]

 

On 21/12/2023 at 15:58, JimC said:

I put this together after a thread on another forum. 
I've always considered that the chief issue with the Great Bear was excessively long fire tubes, but it was pointed out that there was at least one successful locomotive class with 23ft tubes - the German DRG05 4-6-4 that held the steam speed record with 200km/h on essentially level track. I took a look at the numbers, and basically if the Bear's firebox and grate were increased in size by about 25% the resulting proportions aren't so different from the DRG05. So here you are. 

It could also be a fourcylinder simple copy of Goelsdorf 310.Would solve the UK loading gauge problems  allowing a Krauss Helmholtz up front.

 

Edited December 25, 2023 by Niels

[DenysW]

At 3084mm maximum width (10 ft 1.4") that's over-gauge, I'm afraid. But it is a nice locomotive.

[rodent279]

Would be interesting to see what that nice Mr Churchward might have come up with, had he had his eye on the Bayern S3/6 instead of the Nord Atlantics.

[Flying Fox 34F]

18 hours ago, DenysW said:

At 3084mm maximum width (10 ft 1.4") that's over-gauge, I'm afraid. But it is a nice locomotive.

Just rescale the whole drawing to fit an appropriate British Loading Gauge.  There are plenty to choose from.  I’m sure someone can recalculate Tractive Effort of a smaller machine.

 

Paul

[Niels]

On 27/12/2023 at 09:53, Flying Fox 34F said:

Just rescale the whole drawing to fit an appropriate British Loading Gauge.  There are plenty to choose from.  I’m sure someone can recalculate Tractive Effort of a smaller machine.

 

Paul

Let me try.

A Castle has two 406mm dia outside cylinders sitting 2184mm appart.

Mr Garbe in Germany designed a 2-6-0( P6) with full Krauss- Helmholtz front truck and two outside cylinders sitting 2080mm apart.

 

Prussian P6

 

 

 

That means a 2-6-4 with Castle wheels and cylinder dimensions could run the same routes as a normal Castle.

It could even have 508mm outside cylinders and  one inside with 762mm strokes and have more tractive effort than a King.And at lower pressure if wheels were 6 feet diameter

Edited December 30, 2023 by Niels

[Flying Fox 34F]

I see I’ve given you some ideas.  Excellent.

 

Paul

Edited December 28, 2023 by Flying Fox 34F
Additional word

[burgundy]

On 27/12/2023 at 08:53, Flying Fox 34F said:

Just rescale the whole drawing to fit an appropriate British Loading Gauge.  There are plenty to choose from.  I’m sure someone can recalculate Tractive Effort of a smaller machine.

 

Paul

Isn't it obvious? Just build it to HO. 

Best wishes 

Eric  

[Flying Fox 34F]

In a simplistic way, just reduce all dimensions by 12%.  It should fit reasonably.

Ironically, the same figure is the difference between OO and HO!

 

Paul

[rockershovel]

On 14/12/2023 at 19:24, Ohmisterporter said:

 

Eric, thanks for that link. I am not a modeller of the LBSCR but can easily see the attraction. Several hours spent reading this with many more to come I expect.

Geoff.

That's a handsome period loco and I must say, LBSCR modellers seem well provided for!

[Niels]

On 28/12/2023 at 13:38, Flying Fox 34F said:

In a simplistic way, just reduce all dimensions by 12%.  It should fit reasonably.

Ironically, the same figure is the difference between OO and HO!

 

Paul

If You can afford it ,it has already done.Photoshop Coppercap

Click Picture for enlargement.Once ,wait ,Once more.

 

Edited December 31, 2023 by Niels

[The Johnster]

Handsome, elegant, graceful even, very stylish (but so was Dracula) and looks as if it could go like a bat outta 'uddersfield, but could I respectfully suggest some alterations that I feel would gild the lily.  Firstly, there is no need for the boiler furniture and whistle to protrude so much beyond the topline of the cab/firebox, and one doubts that they would survive the first bridge.  I would replace the excessively ornate dome with a Gresley banjo type, and move the whistle & safety valves elsewhere.  The chimney needs to be cut down to cab roof level, and probably doubled (retaining the copper cap), giving the beast more of a mean, lowdown, dirty, evil appearance.  The livery is perfect for this.  The cut down chimney will need smokelifiting apparatus, de Witte almost suggests itself by default.  The driver can only be Dick Dastardly, with Muttley firing.  Oh, and a cone-nosed smokebox door, hinged to open upwards... 

 

Mwahahahaha.

 

Not at all sure about that tender; reckon a Gresley 8-wheeler would be better.

[Flying Fox 34F]

If I had the time, I would restyle to a more typical looking British locomotive.  Perhaps someone else can run with that.

 

Paul

[Gilwell Park]

375.007 is preserved in Prague technical museum, although with a more normal smokebox door.  It looks magnificent and the way the frames are made and everything attached is fascinating. Well worth a visit. Would love to see one in action.