Imaginary Locomotives

[Satan's Goldfish]

I was purely coincidentally just playing with this.

 

Princess

Princess with 8f drivers

Princess with 2800 drivers (and other bits!)

2800

 

[RLBH]

11 hours ago, Satan's Goldfish said:

Princess with 8f drivers

How about 4F drivers? The P1 has the same size wheels as the J39, whose nearest LMS equivalent was the 4F. It seems like a waste of a big boiler putting it on 4' 8"-ish drivers.

[34theletterbetweenB&D]

3 hours ago, RLBH said:

How about 4F drivers? The P1 has the same size wheels as the J39, whose nearest LMS equivalent was the 4F Ivatt Mucky Duck. It seems like a waste of a big boiler putting it on 4' 8"-ish drivers.

And indeed the BR plan for its 9F began as a 5'3" driver 2-8-2. It could usefully have gone larger diameter still. There was little if any need for near 40,000lb starting tractive effort, a better balanced design would have been a 2-8-2 with 6' diameter drivers. The resulting circa 33,000lb starting TE more than adequate for UK freight service, and that loco would have galloped up to 90mph without reservations, just like any mixed traffic type.

 

There's not the adhesion problem with a heavy 2-8-2 either. The P1 was built with a trailing truck booster for 47,000lb starting TE, and this was subsequently removed as unnecessary. It could reliably start the heaviest mineral loads that the line accommodated. Likewise the P2 was found to be able to 'lift' anything. (I believe the GWR had 2-8-2T developed from 2-8-0T, did they slip?)

 

Riddles' move to a 2-10 -0 format was more about the Midland obsession with small axle load. Quite why he thought a 2,000 hp unit should be made fit for light branch work is a mystery. Totally uneconomic lugging all that weight around for a job requiring a two or three hundred horsepower: it's a main line unit and that's where it should stay, give it 22T on each axle.

[RLBH]

3 hours ago, 34theletterbetweenB&D said:

And indeed the BR plan for its 9F began as a 5'3" driver 2-8-2. It could usefully have gone larger diameter still. There was little if any need for near 40,000lb starting tractive effort, a better balanced design would have been a 2-8-2 with 6' diameter drivers. The resulting circa 33,000lb starting TE more than adequate for UK freight service, and that loco would have galloped up to 90mph without reservations, just like any mixed traffic type.

I've a feeling that 72" drivers would be overambitious with a roughly Britannia/9F/Gresley Pacific sized boiler - it probably wouldn't have enough steam to haul a train that justified its' existence at the higher end of the speed range. A locomotive of that capacity really wants a 50 square foot grate.

 

Interestingly, the Fowler 2-8-2, the P1, and the early 9F plans all have broadly similar headline figures. That three different engineers, working for three different railway companies, developed similar plans suggests to me that they were barking up the right tree. Somewhere around there is probably the optimum big 2-8-2 for British main-line freight.

 

There's an interesting possibility for the P1 - the Annesley Runners that the 9Fs made their own. A build of thirty-some P1s for this work seems like it ought to be a success if traffic on the Great Central Main Line would permit.

[34theletterbetweenB&D]

1 hour ago, RLBH said:

I've a feeling that 72" drivers would be overambitious with a roughly Britannia/9F/Gresley Pacific sized boiler

What was wrong with the 9F boiler was the limitation on ashpan capacity brought about by the ten coupled format, making it a relatively short range machine.

 

Consider that the Brits weren't troubled by 74" drivers: deep firebox and ashpan,  maintained a good steam supply all day long, and the very same boiler would go on a 72" wheel 2-8-2. Oh look, economy in design! Same boiler for more than one class. Or just build the whole lot as 2-8-2s,  300 of a high adhesion mixed traffic loco, now that could have been handy. Or spend all the BR standard tender loco funding in this format and have 600?

[Northmoor]

8 hours ago, 34theletterbetweenB&D said:

And indeed the BR plan for its 9F began as a 5'3" driver 2-8-2. It could usefully have gone larger diameter still. There was little if any need for near 40,000lb starting tractive effort, a better balanced design would have been a 2-8-2 with 6' diameter drivers. The resulting circa 33,000lb starting TE more than adequate for UK freight service, and that loco would have galloped up to 90mph without reservations, just like any mixed traffic type.

 

There's not the adhesion problem with a heavy 2-8-2 either. The P1 was built with a trailing truck booster for 47,000lb starting TE, and this was subsequently removed as unnecessary. It could reliably start the heaviest mineral loads that the line accommodated. Likewise the P2 was found to be able to 'lift' anything. (I believe the GWR had 2-8-2T developed from 2-8-0T, did they slip?)

 

Riddles' move to a 2-10 -0 format was more about the Midland obsession with small axle load. Quite why he thought a 2,000 hp unit should be made fit for light branch work is a mystery. Totally uneconomic lugging all that weight around for a job requiring a two or three hundred horsepower: it's a main line unit and that's where it should stay, give it 22T on each axle.

I would still like to see a REAL 2-8-2 9F.....  There was no need for a fast (90mph) 9F, they were freight engines - and arguably the ex-LMS 8Fs could have been distributed around the regions to cover slow/heavy traffic before it was progressively dieselised - while all the regions had the Class 7 passenger power they needed, again, before modern traction arrived.

 

Isn't the problem with the P1 not maximum weight but train length?  All the P1s did was show up how wagon development had stagnated; 1600t freights requiring 100 wagons?  The mechanical engineers should have been seriously looking at bogie hoppers for these bulk hauls (as the LMS did for Derbyshire limestone in the same era).  It would have almost halved the train length.

[Satan's Goldfish]

17 minutes ago, Northmoor said:

I would still like to see a REAL 2-8-2 9F.....  

 

So would that be '9f' 2-8-2 on 9f sized wheels but with a Brit firebox over the rear axle? or on larger driving wheels so it's more like a 2-8-2 Brit (as I've already done that one!)?

[Satan's Goldfish]

10 minutes ago, Satan's Goldfish said:

 

So would that be '9f' 2-8-2 on 9f sized wheels but with a Brit firebox over the rear axle? or on larger driving wheels so it's more like a 2-8-2 Brit (as I've already done that one!)?

 

Here's one I prepared earlier.... and 1 I've quickly rustled up!

 

There's really not much in it apart from the driver size: 5'6" on the Brit derived 2-8-2, and 5' on the 9f derived 2-8-2. So which would be the better option as a BR standard? the Mixed Traffic version or the freight only version? If going with the MT version would there still be some niche requirements for a 9f freight locomotive?

 

 

 

I think i now need to go back and put the 5'6" drivers under a princess...

[RLBH]

2 hours ago, 34theletterbetweenB&D said:

Consider that the Brits weren't troubled by 74" drivers: deep firebox and ashpan,  maintained a good steam supply all day long, and the very same boiler would go on a 72" wheel 2-8-2. Oh look, economy in design! Same boiler for more than one class. Or just build the whole lot as 2-8-2s,  300 of a high adhesion mixed traffic loco, now that could have been handy. Or spend all the BR standard tender loco funding in this format and have 600?

 

My feeling is that a 2-8-2 could start heavier trains than a Britannia (else why bother) but - having the same boiler - wouldn't be able to pull them as fast. In which case, the larger drivers are unnecessary. You pretty much wind up with a Britannia with better adhesion (not to be sniffed at) but poorer riding at speed (thanks to the pony truck rather than a leading bogie). To usefully employ the larger drivers and the potential adhesion of a 2-8-2 you wind up not far off a P2.

[Satan's Goldfish]

13 hours ago, RLBH said:

How about 4F drivers? The P1 has the same size wheels as the J39, whose nearest LMS equivalent was the 4F. It seems like a waste of a big boiler putting it on 4' 8"-ish drivers.

 

Ok, dropped the Princess on some 5'6'' drivers, so a couple of inches bigger than a 4f. I'll agree, it looks better. Cylinders needed moving forward to accommodate the chassis.

 

[Niels]

40 minutes ago, Satan's Goldfish said:

 

Ok, dropped the Princess on some 5'6'' drivers, so a couple of inches bigger than a 4f. I'll agree, it looks better. Cylinders needed moving forward to accommodate the chassis.

 

 

Lovely,but can be even more extreme.

Tests made by BR Rugby showed that 9F boiler was as least as effective as Brittania boiler (that compared very well with LNER V2) as long as it was  at or under 3000 lbs coal per hour,one fireman limit.

Narrow fireboxes would  not have been  worth the trouble on British railways if five feet drivers could have  been made to turn fast enough.

To make five feet drivers fast enough they can be three cylinder driven or by two and then some artificial balancing.

With two outside cylinders and a crankshaft and a dummy conrod inside it will still be ligther than the moving parts of Kings,Royal Scotts and Class 5/B1 .

And just as fast in daily use.

To show it a Photoshop session from a WD 2-10-0 picture will be easy due to the cylindrical round top boiler.

Is there sush a picture somewhere?

 

Something like:

 

WD 2-10-0 side picture

 

 

 

 

Edited March 7, 2019 by Niels

[34theletterbetweenB&D]

20 hours ago, RLBH said:

 

My feeling is that a 2-8-2 could start heavier trains than a Britannia (else why bother) but - having the same boiler - wouldn't be able to pull them as fast. In which case, the larger drivers are unnecessary. You pretty much wind up with a Britannia with better adhesion (not to be sniffed at) but poorer riding at speed (thanks to the pony truck rather than a leading bogie). To usefully employ the larger drivers and the potential adhesion of a 2-8-2 you wind up not far off a P2.

But you don't need all that capability for all classes of traffic. The point about a larger wheeled 22T axleload 2-8-2  with the Britannia boiler is that it has the high adhesion to be an effective slow freight machine, capable of reliably starting and dragging around 1200T at circa 25mph, and can also work as a fast freight machine able to move a fitted freight loading circa 600T on a 50mph schedule, and an express passenger machine good for 90 mph peak speed on a 70mph schedule with a 400T load. (There simply weren't the freight loads for a P2 or a P1 with steam era rolling stock, and this wasn't fixed until fully fitted bogie freight stock became dominant well after steam ended.)

 

There was an earlier mixed traffic loco design which could do all this, save that its adhesion required careful management when starting a heavy mineral haul on a poor rail. That was the V2 2-6-2. Add another coupled wheelset to this machine and there's a loco good for practically all heavy UK main line duties.

[melmerby]

3 hours ago, 34theletterbetweenB&D said:

But you don't need all that capability for all classes of traffic. The point about a larger wheeled 22T axleload 2-8-2  with the Britannia boiler is that it has the high adhesion to be an effective slow freight machine, capable of reliably starting and dragging around 1200T at circa 25mph, and can also work as a fast freight machine able to move a fitted freight loading circa 600T on a 50mph schedule, and an express passenger machine good for 90 mph peak speed on a 70mph schedule with a 400T load. (There simply weren't the freight loads for a P2 or a P1 with steam era rolling stock, and this wasn't fixed until fully fitted bogie freight stock became dominant well after steam ended.)

 

There was an earlier mixed traffic loco design which could do all this, save that its adhesion required careful management when starting a heavy mineral haul on a poor rail. That was the V2 2-6-2. Add another coupled wheelset to this machine and there's a loco good for practically all heavy UK main line duties.

The GWR had a loco that should be capable of 90mph, cruise at 70 mph and pull lots of freight - the 47XX

Whether it ever reached 90mph is another matter although the Grange, which only had 5.2% less tractive effort but was a 4-6-0 could.

 

Surely a V2 with an extra set of coupled wheels is a P2?

 

Why not a 2-8-2 version of Peppercorn's superb A2? Even more of a P2!

Edited March 8, 2019 by melmerby

[Satan's Goldfish]

On 08/03/2019 at 18:02, 34theletterbetweenB&D said:

There was an earlier mixed traffic loco design which could do all this, save that its adhesion required careful management when starting a heavy mineral haul on a poor rail. That was the V2 2-6-2. Add another coupled wheelset to this machine and there's a loco good for practically all heavy UK main line duties.

 

Im sure I've played with the V2 previously but can't remember why... for the more learned then; what size are a V2s drivers? And fire box/boiler/smoke box length compared to an A1-A3?

[34theletterbetweenB&D]

7 minutes ago, Satan's Goldfish said:

 

Im sure I've played with the V2 previously but can't remember why... for the more learned then; what size are a V2s drivers? And fire box/boiler/smoke box length compared to an A1-A3?

The V2 was a 2-6-2 with 6'2" drivers and a foot shorter barrel variant of the Doncaster 'Gresley' pacific boilers with  41.25 sq ft grate area. https://www.lner.info/locos/V/v2.php

[Gibbo675]

Hi Chaps,

 

All this talk of great big 2-8-2's and such, along with what they may be able to haul and at what sort of elevated speeds they may be able to work at seems to somewhat miss the fact that most of the goods wagons were not fitted with continuous brakes, and also that most of those that were did not have D-A valves. It would seem that a lot of metal spaghetti would be created due to such a locomotive's inability to stop the trains that they would be able to not only start but also haul at elevated speeds.

 

My experience of working vacuum brakes and how delayed the action of them is was on the footplate of 46229 while approaching Tebay on the up line. With the speedo needle just under 85 mph we sighted a double yellow, the brake was applied and with the vacuum gauge reading zero it took a good fifteen seconds to feel a full bite from the brakes and to observe the speedo needle to start to fall rather than rise. In that time we would have travelled about 3/8 of a mile. Granted, goods trains tended not to descend Shap Bank at 85 mph but I feel it illustrates the point.

 

We need to look at locomotives that are provided with air brakes and fully fitted goods wagons to suit. I am of the firm knowledge that the most important control upon the footplate was the brake handle !

 

I am of course guilty of this sort of nonsense with my great big BR Non-Standard Mallet and Kitson-Meyer types that I have previously posted.

 

Gibbo.

[melmerby]

Maybe we should digress into the field of properly braked bogie goods wagons?

Then these 8 coupled beasts would have something suitable to gallop along with

Edited March 10, 2019 by melmerby

[Corbs]

There's an 'imaginary rolling stock' thread for exactly that

[34theletterbetweenB&D]

Verily, as the one who started it wrote:

Should I ever grace my operation with a Doncasteresque 2-8-2, I think some continuously braked bogie mineral

vehicles with a discernible relationship to the NER's 'Ashington' hoppers might have to be provided as well. I feel it is reasonable to suppose that the NER's proven bulk handling approach might have been thus progressively enlarged upon, had the times been more propitious.

[Niels]

Steam locomotive drivers was sometimes more than five feet because two cylinder locomotives shake themself to death and destruction with  number of rpm squared.

Three  cylinder locomotives are inherently well balanced so five feet drivers would have been big enough for most trains.

 

 

Based on 9F wheels and boiler form tools.And was nice to dream on a rainy day like today.

http://

Edited March 14, 2019 by Niels

[Gibbo675]

54 minutes ago, Niels said:

Steam locomotive drivers was sometimes more than five feet because two cylinder locomotives shake themself to death and destruction with  number of rpm squared.

Three  cylinder locomotives are inherently well balanced so five feet drivers would have been big enough for most trains.

 

 

Based on 9F wheels and boiler form tools.And was nice to dream on a rainy day like today.

http://

Hi Niels,

 

I hate to be a spoil sport but the thing is, there is a lot more that just wheel diameter to be considered if you want to go fast.

 

For one thing keeping the front end tight when the mean average piston speed creeps up is quite a trouble. Problems such as cylinder wear (tapering, barrelling, and general increased wear rate), piston head wear, leaking gland packings, cross head wear, ring breakage, ring groove tapering, piston rod wear all have to be factored in.

 

Axle boxes along with the pins and bushes of the rods and motion will take a pounding. Even if the axle boxes are fitted with manganese steel liners this may increase service interval of the axle boxes but may not prevent; loose horn ties, loose horn blocks, frame fractures, fractured or loose frame stretchers even loose cylinders.

 

This is with considering the stress reversals that effect the masses of all reciprocating components which is part of the design criteria that define the sections required to transmit the forces of an engine of a particular speed and power output.

 

A 9F at 30 mph has a mean average piston speed of 13.06 feet per second, at 60mph 26.13 feet/sec and at 90 mph 39.2 feet/sec.

 

Most locomotives have a optimum upper bound operating speed equivalent to one inch of driving wheel per mile per hour with a 25% allowance for maximum operating speed. This figure may rise for short stroke locomotives and also the ratio is improved with larger diameter wheels and short stroke engines. Unfortunately the 9F is somewhat over square with a long stroke and small wheels for fast work having a mean average piston speed of 32.66 feet per second at 75 mph.

 

I do like the 2-8-0, I might bash a Dapol kit now that I have looked at it !

 

Any questions, do ask.

 

Gibbo.

Edited March 12, 2019 by Gibbo675
2-8-0 mention

[Niels]

null

On 12/03/2019 at 22:14, Gibbo675 said:

Hi Niels,

I do like the 2-8-0, I might bash a Dapol kit now that I have looked at it !

Gibbo.

 You aint seen nothing yet.

 

https://i.imgur.com/RqN3dGA.jpg

 

Edited March 14, 2019 by Niels

[Corbs]

Another 'advanced steam' type loco

https://www.martynbane.co.uk/modernsteam/ldp/lvm/lvm800.htm

 

3 cylinder compound 0-6-0T or 0-6-2T for shunting, running on biomass fuel.

 

Concept art by Robin Barnes

 

[The Johnster]

Aw, look at it's cute little nose and those pince-nez it's wearing!

 

If the fuel is to be fed in to the firebox by gravity from the hopper on top, it needs to be graded and compacted into pellets or balls so that blockages are not caused, and this process might upset the economic viability of the loco.  Don't like the position of the tank fillers, which block the driver's forward view and negate the advantage gained from sloping the top of the tank; low level filling from a pumped supply might suit this loco better.  I'm assuming that it's for industrial use and will never be more than a few hundred yards from base.

 

If some method could be devised of opening the entire smokebox, hinged at the front of the boiler, it might aid smokebox and boiler cleaning and would certainly improve access to the hp cylinder and it's associated motion without anyone having to go underneath the loco.

[Corbs]

Have a look at the link, it's part of a much bigger proposal they worked up

 

Today's nonsense.

 

An Ivatt Super-8F 4-8-0

3 cylinder front end similar to Royal Scot/Jubilee etc. Double chimney

Bigger firebox than an 8F - wheelbase has been enlarged to accommodate this.

Ivatt style cab