Imaginary Locomotives

[Satan's Goldfish]

And now, I've 8f Mikado'd DoG...... it's a bit sloppy in places, I don't like the big space between the boiler and the wheels as a lot of that could be neater, I'm not sure what all the various rods around the cylinders are supposed to do, maybe the cylinders should have been sloped like a 9fs rather than just lowered but DoG's cylinders/valves are mostly what makes it different. Any of the educated be able to reclassify the power rating for me?!

 

[Satan's Goldfish]

Last pointless locomotive for the night, the LMS Mountain. Drivers and front pony are from a black 5, distance reduced between rear drivers. Boiler and deflectors extended only slightly.

 

 

Would have preferred to make that a Mikado and kept the original boiler and deflector lengths, but that would have been a lot of work to reposition cylinders and rods..... maybe next time, That'd probably make a much better set of drivers for the DoG Mikado above.

 

 

[Gibbo675]

1 hour ago, Satan's Goldfish said:

And now, I've 8f Mikado'd DoG...... it's a bit sloppy in places, I don't like the big space between the boiler and the wheels as a lot of that could be neater, I'm not sure what all the various rods around the cylinders are supposed to do, maybe the cylinders should have been sloped like a 9fs rather than just lowered but DoG's cylinders/valves are mostly what makes it different. Any of the educated be able to reclassify the power rating for me?!

 

Hi Mr Goldfish,

 

The tractive effort calculation for a two cylinder is as follows:

 

TE = ( d X d X p X s / w ) X .85

 

• d = Piston diameter in inches.
• p = Maximum boiler pressure in pounds per square inches.
• s = Stroke of piston in inches.
• w = Wheel diameter in inches.

For four cylinders multiply the answer by two and for three cylinders by one and a half.

 

I would have worked it out but you have not furnished us with leading dimensions as noted above.

 

Gibbo.

Edited February 12, 2019 by Gibbo675
Sub and super script have been removed and so I have had to use d X d !

[Satan's Goldfish]

2 minutes ago, Gibbo675 said:

Hi Mr Goldfish,

 

The tractive effort calculation for a two cylinder is as follows:

 

TE = ( d X p X s / w ) X .85

 

• d = Piston diameter in inches.
• p = Maximum boiler pressure in pounds per square inches.
• s = Stroke of piston in inches.
• w = Wheel diameter in inches.

For four cylinders multiply the answer by two and for three cylinders by one and a half.

 

I would have worked it out but you have not furnished us with leading dimensions as noted above.

 

Gibbo.

 

 

Cheers Gibbo, tbh I'm none the wiser really! However I have lied a bit above and did have another play with sorting out a 2-8-2 wheel base based on the black 5 drivers and the revised DoG Mikado is below. Everything is standard DoG and what ever its 3 cylinder dimensions are, but with whatever size Black 5 drivers are!

 

 

It needed to gain an almost unnoticeable couple of inches of length to the smoke box to fit the new wheel base, but that's the only difference to the body of the original engine. I'm much happier with this than the version using 8f drivers. 

[Gibbo675]

7 minutes ago, Satan's Goldfish said:

 

 

Cheers Gibbo, tbh I'm none the wiser really! However I have lied a bit above and did have another play with sorting out a 2-8-2 wheel base based on the black 5 drivers and the revised DoG Mikado is below. Everything is standard DoG and what ever its 3 cylinder dimensions are, but with whatever size Black 5 drivers are!

 

 

It needed to gain an almost unnoticeable couple of inches of length to the smoke box to fit the new wheel base, but that's the only difference to the body of the original engine. I'm much happier with this than the version using 8f drivers. 

Hi There,

 

Seventy one million's cylinders are 18" d X 28" s and Black Fives have 72" driving wheels when new, boiler pressure 250 lbs.

 

If you wish to work out the adhesion factor then you have to divide the total driven axle loadings in pounds by the tractive effort.

 

Seventy one million has a total driven axle loading of 147840 lbs (three axles at 22 tons) and a tractive effort of 39080 lbs giving an adhesion factor of 3.78.

 

Gibbo.

Edited February 12, 2019 by Gibbo675

[AlfaZagato]

Someone should double-check, but I came up with 40162.5lbs. for tractive effort with Black Five drivers.

[Satan's Goldfish]

3 minutes ago, AlfaZagato said:

Someone should double-check, but I came up with 40162.5lbs. for tractive effort with Black Five drivers.

 

That's what I've got too, I think there may be an error somewhere as that's nearly 4x the highest band listed here! https://en.wikipedia.org/wiki/LMS_locomotive_numbering_and_classification

[AlfaZagato]

I questioned the final x0.85, then multiplying by 1.5 for the three-cylinders, but if we're that high, I can't say.

[Satan's Goldfish]

6 minutes ago, AlfaZagato said:

I questioned the final x0.85, then multiplying by 1.5 for the three-cylinders, but if we're that high, I can't say.

 

Just double checked against this: https://en.m.wikipedia.org/wiki/Tractive_force the formula looks the same and the resulting number definitely isn't as high as some of the American claims beneath it so could be right... both are quoting tractive effort in lbf... and according to wiki a 9f is just short of 40000lbf.

Edited February 12, 2019 by Satan's Goldfish

[rodent279]

I think a Duchess with 6' wheels, remodelled as a 2-8-2 or 4-8-2 is an intriguing proposition, and one that just might have seen the light of day, had nationalisation and dieselisation not happened. Or perhaps, a better description would be a Black 5 with a Duchess boiler and extra wheels.

[melmerby]

IF DoG drivers are 74" & Black 5s are 72" and DoG has a TE of 39080

All you need to do the tractive effort is 74/72 X 39080 = 40165.555lbs

It's just the difference in wheel size.

Similarly if you put Coronation drivers on DoG you would get just over 35700lbs

 

Likewise if you take a Coronation with a TE of 40000 and put P2 wheels on it you get 81/74 X 40000 = 43784lbs which is a bit more than a P2

What's this about the P2 being Britains most powerful loco?

 

Edited February 12, 2019 by melmerby

[Gibbo675]

1 minute ago, melmerby said:

IF DoG drivers are 74" & Black 5s are 72" and DoG has a TE of 39080

All you need to do the tractive effort is 74/72 X 39080 = 40165.555lbs

It's just the difference in wheel size.

 

Similarly if you take a Coronation with a TE of 40000 and put P2 wheels on it you get 81/74 X 40000 = 43784lbs which is a bit more than a P2

What's this about the P2 being Britains most powerful loco?

 

Hi Kieth,

 

Tractive effort is not power, please don't send any one down that particular route of thinking.

 

Treactive effort of a 350 hp class 08 shunter is 36000 lbs.

 

Think about it !!!

 

Gibbo.

[melmerby]

Yes I know but TE was being quoted so I interjected.

The P2 people often quote it for their machine!

Edited February 12, 2019 by melmerby

[Gibbo675]

31 minutes ago, Satan's Goldfish said:

 

That's what I've got too, I think there may be an error somewhere as that's nearly 4x the highest band listed here! https://en.wikipedia.org/wiki/LMS_locomotive_numbering_and_classification

Hi Mr Goldfish,

 

The table shews tractive effort at determined speeds, 50mph for passenger locomotives and 25mph for goods locomotives. The calculation that you are using is start tractive effort that is 0mph.

At speed the cut off is reduced so that the engines of the locomotive may be worked more expansively improving efficiency resulting in ta reduction of tractive effort.

 

The figure of .85 pertains to the mean average steam pressure from the point of admission when the valve opens at the pistons lead position until the opposite edge of the valve opens to exhaust at 75% cut off. When the cut off is reduced so is the mean average steam pressure, remember exhaust is set function via the action of the combination lever as is the lead function.

 

The LMS 4-6-4 Super Duchess had a start tractive effort of 42850 lbs and the 4-8-4 goods locomotive 47600 lbs with axle loading of 24 tons and 20 tons each. Both had 17.5" X 28 " cylinders and 6'6" and 5' 6" driving wheels with adhesion factors of 3.75 and 3.77 respectively. The maximum cut off would have been reduced to around 65% instead of the more usual 75-78% giving high tractive effort at designed running speed without causing the adhesion factor to be to low that slipping upon starting would be a serious problem.

 

Gibbo.

 

 

[RLBH]

7 hours ago, Gibbo675 said:



At speed the cut off is reduced so that the engines of the locomotive may be worked more expansively improving efficiency resulting in ta reduction of tractive effort.

The general rule is that traditional steam locomotives are limited by tractive effort, whilst electric-drive locomotives are limited by power. Or in other words, a steam loco can pull at speed anything that it can get moving, whilst a (diesel-)electric can start anything that it can pull at speed.

 

The 2-8-2 using a Duke of Gloucester boiler and 72" drivers comes out as having a BR classification of 8P9F, as does any large locomotive - the system isn't designed to go that high. Tractive effort is 40,160 lbf, as noted, above, with a Power Factor of 1,327 - still slightly short of a Coronation or P2. I'd estimate axle loads as 19 tons 14 cwt on the drivers, 6 tons 11 cwt on the pony truck, and 16 tons 3 cwt on the trailing truck, giving a factor of adhesion of 4.37 and 78% of weight on drivers. The load on the pony truck might be considered a little light, it could be increased by offloading the drivers slightly.

[Satan's Goldfish]

Just to finish off the collection then:

 

[LNWR18901910]

You may be interested to know that a book by Robin Barnes explains and shares details on many what-if engines. The book is entitled “Locomotives that Were & Locomotives that Weren’t” and I was thinking of buying it and reading it.

https://www.advanced-steam.org/ast-news/robin-barnes-new-book-now-available/

https://www.camdenmin.co.uk/products/from-the-files-locomotives-that-were-locomotives-that-weren-t

[34theletterbetweenB&D]

On ‎13‎/‎02‎/‎2019 at 07:23, RLBH said:

...The 2-8-2 using a Duke of Gloucester boiler and 72" drivers comes out as having a BR classification of 8P9F, as does any large locomotive - the system isn't designed to go that high. Tractive effort is 40,160 lbf, as noted, above, with a Power Factor of 1,327 - still slightly short of a Coronation or P2...

When we get an OO RTR P2 with the final evolution of exterior form that the LNER devised, I intend to operate one in BR lined green (unsteady Eddie never happened) with 9MT on the cab sidesheets. It will operate a special fast fully fitted goods turn that provides enough loading to make economic use of its capability.

 

In my opinion the loco that would have been more useful than such a 40,000lb + TE type - whether the P2 as the sole big wheel 2-8-2 operated in the UK, or derived from the boilers and front ends of 8P pacifics such as Duchess, DoG or MN - is the Britannia reworked into a 6' driver 22T axle load 2-8-2. That should produce a loco capable of handling 95%+ of BR's heavy main line turns from slow freight to fast passenger, with the considerable advantage of a much higher adhesion factor than a UK pacific.

[Joseph_Pestell]

4 minutes ago, 34theletterbetweenB&D said:

When we get an OO RTR P2 with the final evolution of exterior form that the LNER devised, I intend to operate one in BR lined green (unsteady Eddie never happened) with 9MT on the cab sidesheets. It will operate a special fast fully fitted goods turn that provides enough loading to make economic use of its capability.

 

In my opinion the loco that would have been more useful than such a 40,000lb + TE type - whether the P2 as the sole big wheel 2-8-2 operated in the UK, or derived from the boilers and front ends of 8P pacifics such as Duchess, DoG or MN - is the Britannia reworked into a 6' driver 22T axle load 2-8-2. That should produce a loco capable of handling 95%+ of BR's heavy main line turns from slow freight to fast passenger, with the considerable advantage of a much higher adhesion factor than a UK pacific.

 

I believe you can get a resin body shell for P2 in later form. Not convinced that we will see one in rtr.

[RLBH]

12 minutes ago, 34theletterbetweenB&D said:

It will operate a special fast fully fitted goods turn that provides enough loading to make economic use of its capability.

Or, indeed, the 2,000 ton cement train that it took an A2/3 to get up Stoke Bank on time. A 2-8-2 would be just the thing for that sort of work - as indeed Gresley must have been thinking when he designed the P1!

[34theletterbetweenB&D]

34 minutes ago, Joseph_Pestell said:

 

I believe you can get a resin body shell for P2 in later form. Not convinced that we will see one in rtr.

An old Bachmann A4 shell will donate parts for the job should this not happen. But I remain pretty confident this will emerge. There is a general shortage of new large steam loco subjects...

[Corbs]

A caprotti mikado streamlined Duchess, I think that's my favourite so far!

[Dr Gerbil-Fritters]

10 minutes ago, Corbs said:

A caprotti mikado streamlined Duchess, I think that's my favourite so far!

 

aka,The Flying Bathtub  

[melmerby]

13 hours ago, Joseph_Pestell said:

 

I believe you can get a resin body shell for P2 in later form. Not convinced that we will see one in rtr.

It's been designed for one.

The chassis has the required slope at the front

[Flying Pig]

On 14/02/2019 at 09:33, 34theletterbetweenB&D said:

In my opinion the loco that would have been more useful than such a 40,000lb + TE type - whether the P2 as the sole big wheel 2-8-2 operated in the UK, or derived from the boilers and front ends of 8P pacifics such as Duchess, DoG or MN - is the Britannia reworked into a 6' driver 22T axle load 2-8-2. That should produce a loco capable of handling 95%+ of BR's heavy main line turns from slow freight to fast passenger, with the considerable advantage of a much higher adhesion factor than a UK pacific.

 

Close to A. J. Powell's heavy 2-8-2 which he rated at 7P9F, 36,000lbs using a Britannia boiler and slightly modified cylinders. Estimated axle weight of just 17 tons and 5' 6" coupled wheels to reuse parts from the Stanier 2-6-0s.