Imaginary Locomotives

[RedGemAlchemist]

14 hours ago, relaxinghobby said:

A distraction from all the big stuff now, a late nineteenth century secondary line passenger type. I was trying to find a drawing of a McConnell Kerry Bogie for the Great Southern and Western Railway of Ireland but only found a couple of drawings of similar locos from the mainland. A Sharp Stewart for the Cambrian Railways, a Dubs for the Midland and South-Western Rly and a slightly larger McConnell he built for the North Eastern mainline. Built for long but lightly populated routes, there is a picture of the Kerry bogie jogging along with a train of a van and 4 six wheelers. All very nice and rural. So my drawing is an an averaged out amalgamation of this type of loco,8 foot wheel base for the drivers, 20ft to 20 ft 6 in overall wheelbase, 5ft 6 to 6ft 6 diameter drivers and about a 4 ft diameter boiler, although in this diagram one nearly 5 foot is shown, I might use a molding I already have.

Cute. Let me know how it goes. I still want a 4-4-0 and it'd be nice to see how you get on. 

[Niels]

On 16/08/2019 at 12:01, Niels said:

Thank you

Drag plate area was then 154 * 0.215=33 square meter

Air power 0.5 *1.23*(56.5**3)*33=3660kW.

Rolling took 345 kW and thus total was 4015 kW and 1150 came from gravity.

Mallard must have given 2865kW or 3892 horsepower and that is impossible.

The drag plate per meter train was estimated from a known danish case and danish loading gauge and trains  are wider and higher than UK trains.

If we asume that a tape around a uk train is 15% shorte than a continental it calculates to 2300 kW locopower or 3133horsepower  or more or less what was the absolute max measured on a LMS Pacific.

If we asume UK trains have a drag plate area of ca 0.215*.85=0.18 square meter per meter train length we can use it to calculate power demand versus speed from locomotives be they ,steam,diesel or electric.

 

It is maybe of interest to see if the power model is realistic.

Does someone know how long the train was that ran 100 mph pulled by Tornado and aproximate mass of wagons?

I have read that it was on level road and not assisted by diesel at the rear?

[Compound2632]

On 15/08/2019 at 18:04, Niels said:

 

We can make a train power/speed  calculator that is based on first years physics if we use sensible units.

I have never been using apps or excel sheets but did lots of Fortran.

 

Please help.

 

Power(W)  is used to overcome rolling resistance, gradients and air resistance.

 

We need mass of complete train  in kg,

length of complete train in m

Gradient.

Air density is asumed 1.23 kg/cubic metre for over90% of trains worldwide.

g is not 9.81 but 10.Here

Velocity m/sec

 

Rolling resitance is ( 0.0015 times g times mass.) (Newton) and multiplied with speed we get rolling power.

 

Small Gradient (from level where gradient is infinite to 1/200)  power (W) is mass times g times horizontal  velocity divided by  gradient

 

Air resistance  is dynamic pressure( 0.5 times  air density times velocity power two) times equivalent drag plate area.

Air resitance power is air resistance multiplied by velocity.

Equivalent drag plate area for trains (trains are much longer than wide or high) is proportional to length of train and we must estimate it from known runs but can use it for other kinds of trains.

 

 

One does not need absolute values for variables such as rolling resistance to analyse data for, say, a train descending a steady gradient - City of Truro on Wellington bank is a classic example. On the assumption that the resistance (friction and air) of the train increases as a smooth function with velocity, and allowing for the measurement uncertainty due to the precision of Rous-Marten's stopwatches - 0.2 s - it is evident that to achieve the timing Rous-Marten gives for the last quarter-mile, the power produced by the locomotive had to have suddenly increased - which would be quite unphysical. 

[rodent279]

29 minutes ago, Niels said:

 

It is maybe of interest to see if the power model is realistic.

Does someone know how long the train was that ran 100 mph pulled by Tornado and aproximate mass of wagons?

I have read that it was on level road and not assisted by diesel at the rear?

Not sure how many coaches that particular train was, but a typical Mk1 is around 35t, and just over 19m long. A typical railtour rake of 12 coaches would be 420t, and ~230m long.

[Niels]

29 minutes ago, rodent279 said:

Not sure how many coaches that particular train was, but a typical Mk1 is around 35t, and just over 19m long. A typical railtour rake of 12 coaches would be 420t, and ~230m long.

 If 12coaches can be confirmed it means a 585 tons train ,250 m long doing 44m per scond on level rail and no wind.

 

Rolling resistance power 386 kW asuming  0.0015 as coefficient

Airwork comes as 2360 kW that is 2740kW/3727horsepower total.

That is way out of this world so either train was shorter,pushed by diesel or my numerical model is wrong.

Edited September 1, 2019 by Niels

[rodent279]

20 minutes ago, Niels said:

 If 12coaches can be confirmed it means a 585 tons train ,250 m long doing 44m per scond on level rail and no wind.

 

Rolling resistance power 386 kW asuming  0.0015 as coefficient

Airwork comes as 2360 kW that is 2740kW/3727horsepower total.

That is way out of this world so either train was shorter,pushed by diesel or my numerical model is wrong.

What are the figures for 10 or 8 coaches? Are they more believable?

[Niels]

48 minutes ago, rodent279 said:

What are the figures for 10 or 8 coaches? Are they more believable?

 

for 10coaches it will be2330kW/3165hp and for 8  1920 kW/2610 horsepower

2610 horsepower needs a lot of steam.

Will calculate

V2 had same boiler as A4 and same gas resistance as an A1 and gave 31000 lbs/hour steam and 1990 indicated horsepower as absolute maximum for more than a few minutes.

 

Edited September 1, 2019 by Niels

[rodent279]

Then I can only assume it was not level track, or there was a heck of a wind behind it! I would think a tour would be a minimum of 8, probably 10, to make it pay.

[Niels]

1 minute ago, rodent279 said:

Then I can only assume it was not level track, or there was a heck of a wind behind it! I would think a tour would be a minimum of 8, probably 10, to make it pay.

Or my 0.18squaremeter drag-flat-plate-area per trainmeter is to big.

The former Mallard calculation gave also very high  horsepower values.

[rue_d_etropal]

On 28/08/2019 at 20:36, relaxinghobby said:

A distraction from all the big stuff now, a late nineteenth century secondary line passenger type. I was trying to find a drawing of a McConnell Kerry Bogie for the Great Southern and Western Railway of Ireland but only found a couple of drawings of similar locos from the mainland. A Sharp Stewart for the Cambrian Railways, a Dubs for the Midland and South-Western Rly and a slightly larger McConnell he built for the North Eastern mainline. Built for long but lightly populated routes, there is a picture of the Kerry bogie jogging along with a train of a van and 4 six wheelers. All very nice and rural. So my drawing is an an averaged out amalgamation of this type of loco,8 foot wheel base for the drivers, 20ft to 20 ft 6 in overall wheelbase, 5ft 6 to 6ft 6 diameter drivers and about a 4 ft diameter boiler, although in this diagram one nearly 5 foot is shown, I might use a molding I already have. 

Drawing for Kerry Bogie(D19 I assume) are in Model Railways magazine February 1976 issue.

[sir douglas]

saw this yesterday at Telford, a live steam 5AT inspired 4-8-0, from what i can remember the owner saying, the cab is czecg, the boiler is LMS princess, the bogies are french, german smoke deflectors and the tender body is part stanier and part SR or something like that. not just 5AT inspire aesthetically but mechanically also. something in the exhaust which i forget what its called. the axleboxes and crankpins all have roller bearings

[The Johnster]

Lempor exhaust?

[Niels]

On 16/08/2019 at 12:01, Niels said:

Thank you

Drag plate area was then 154 * 0.215=33 square meter

Air power 0.5 *1.23*(56.5**3)*33=3660kW.

Rolling took 345 kW and thus total was 4015 kW and 1150 came from gravity.

Mallard must have given 2865kW or 3892 horsepower and that is impossible.

The drag plate per meter train was estimated from a known danish case and danish loading gauge and trains  are wider and higher than UK trains.

If we asume that a tape around a uk train is 15% shorte than a continental it calculates to 2300 kW locopower or 3133horsepower  or more or less what was the absolute max measured on a LMS Pacific.

If we asume UK trains have a drag plate area of ca 0.215*.85=0.18 square meter per meter train length we can use it to calculate power demand versus speed from locomotives be they ,steam,diesel or electric.

 

The danish IC3 train has been recalculated using better information for wheelpower and comes to 0.15 squaremeter per meter train length.

Mallards train had smaller crossection so let us say 0.13square meter per meter train.

Air resistance area for Mallard plus train can then be estimated to 154*0.13=20 squaremeter and airpower uses 2215 kW,rolling takes 345 and gravity gave 1150.

Mallards input can be calculated 2215+345-1150=1410kW/1915 horsepower and that is realistic according to Cox for a V2.

[Niels]

13 hours ago, rodent279 said:

What are the figures for 10 or 8 coaches? Are they more believable?

Tornado doing 100mph with 8 coaches and the drag plate area 0.13 squaremeter per meter train calculates  to 1990 indicated horsepower or almost exactly what a V2 could give with more tube area but less firebox.

IWe are very close to a  simple formula for calculating needed horsepower knowing total length and mass of train, if Tornado took 8 at 100.

Edited September 2, 2019 by Niels

[sir douglas]

1 hour ago, The Johnster said:

Lempor exhaust?

 

perhaps

[rodent279]

4 hours ago, Niels said:

Or my 0.18squaremeter drag-flat-plate-area per trainmeter is to big.

The former Mallard calculation gave also very high  horsepower values.

Having googled for Tornado's 100mph run, I believe it was a test, done at night, with a rake of Mk2's. The rolling resistance is probably lower than mk1 stock, and the weight is likely to be more like 33t per coach. Being a test train, it may have been a short rake, but I can't find any definitive info on it.

Someone must know-the truth is out there!

Edited September 1, 2019 by rodent279

[The Johnster]

Rolling resistance should be less than mk1 stock with B1 bogies, but Commonwealths and B4s have roller bearings, and are fitted to many mk1s.  Weight is around 32-33 tons for both mk1 and mk2 stock, but the atmospheric resistance of mk2 stock should be less at speed.  The difference will be marginal at best though.

[John M]

On 26/08/2019 at 08:17, Gibbo675 said:

 

I also bought a 9F kit to cut and shut into a crazy hump shunting and banking engine with an articulated booster bunker. I quite like it but it is odd looking and that is with the Kitson-Meyer in the background of the photograph !

 

BR  2-8-4-2 hump shunting and banking locomotive.

 

 

 

Gibbo.

 

The 2-8+4-2T  appears similar in principal to an Engerth Locomotive where the tender is articulated with loco frame. https://en.wikipedia.org/wiki/Engerth_locomotive

The type seems to have been fairly widespread in the Austro-Hungarian Empire and a number survive in preservation

On some locos the tender wheels were driven off a crankshaft like a geared loco!

[DavidB-AU]

7 hours ago, rodent279 said:

Having googled for Tornado's 100mph run, I believe it was a test, done at night, with a rake of Mk2's. The rolling resistance is probably lower than mk1 stock, and the weight is likely to be more like 33t per coach. Being a test train, it may have been a short rake, but I can't find any definitive info on it.

Someone must know-the truth is out there!

 

It was 2 x Mk 1 (support coaches), 7 x Mk 2 and a 67. Slow to 0.25x speed at 0:44.

 

 

Cheers

David

[Niels]

1 hour ago, DavidB-AU said:

 

It was 2 x Mk 1 (support coaches), 7 x Mk 2 and a 67. Slow to 0.25x speed at 0:44.

 

 

Cheers

David

Was it diesel supported?

Edited September 2, 2019 by Niels

[DavidB-AU]

1 hour ago, Niels said:

Was it diesel supported?

 

The diesel was there as backup and for ETS.

 

Cheers

David

[Niels]

1 hour ago, DavidB-AU said:

 

The diesel was there as backup and for ETS.

 

Cheers

David

Was it draging or pushing?

[DavidB-AU]

It was being dragged for the test.

 

Cheers

David

[Niels]

49 minutes ago, DavidB-AU said:

It was being dragged for the test.

 

Cheers

David

 

Damned.

My simple power model shot down in flames

But thank You for answering

[Gibbo675]

11 hours ago, John M said:

 

The 2-8+4-2T  appears similar in principal to an Engerth Locomotive where the tender is articulated with loco frame. https://en.wikipedia.org/wiki/Engerth_locomotive

The type seems to have been fairly widespread in the Austro-Hungarian Empire and a number survive in preservation

On some locos the tender wheels were driven off a crankshaft like a geared loco!

Hi John,

 

Thanks for the link, it is of a type of locomotive I didn't actually know existed for real despite having just made one up !

 

Gibbo.