Niels

I for one would like one of Your countless A2/2s with wedge cab. Running ability does not matter. Modify one side a little and take it along and show mr Thompson what he should have done and ask why he did not. There must be an interesting story there. In 1923-5 all Raven front wheel driven Pacifics had new crankshafts . Ravens son died in WW1. Raven out in the cold. When Thompson had to do something to the crank and rail-breaking P2s he goofed,even if Ravens frontwheel B16 was a succes. Strange.

As I understand it ,it was a long long journey with only a single unionized fireman at a time. That is less than 3000lbs coal per hour. The A2/2 advantage was maybe that the grate did not go haywire so soon. In the calculation of starting/dead slow effort it is also nessecary to include wheel diameter and pressure. The important thing for haulage is adhessive mass; 66 tons for the A2/2 and V2 and 77 for 9F The downside to a big grate is that it wastes more coal all the time with fire.

Exactly. Thank You. My next step is to make a 4-8-0 three cylinder compound version with nicer footplating

A duchess is 5% heavier and uses roughly 10% more steam and coal for making same number of horses

Some thinks that LNER cabs and round top boilers look better than the LMS things. If LNER people had got the top jobs instead of Riddles /Cox a 9F would have looked different. Does it sound to obscene to put this nice 3D printed Cab/Boiler alongside a 9F model (if You have one of course) and make a picture? I have bought a Dapol Evening star and a Bachmann V2 boilerCab so I can make the scheme myself. Best British locomotive coming : Three cylinder Compound 4-8-0 (improved 9F) with Cab and boiler from LNER V2 Money makes the world go round

Do You plan to supply wedge fronted cabs to modify the new Hornby A2/2s? Hornby will not model the real Thompson shape as I understand the anouncement.

To follow up on posting above Thomson could also have ordered : Two simple outside and some kind of extra balancing between frames Two inside like B12 and some outside counterbalancing Three cylinder compound ala Sauvage /Smith One low pressure between frames and one high pressure on starboard side and a counter balancer on other outside. According to a German 1942 source, fuel for same work will be from 114 for a three cylinder simple to 100 for a two cylinder compound It is my hope to be able to convince mr Thompson that his scheme can be improved somewhat. I cannot afford four full size A2/(4 , 5, 6 and 7) but two or three modified Hornbys is possible. Thank You Hornby.

I have looked up the (BR Rugby) boiler efficiency tests of Britannia/9F (Belpaire) and V2 (same boiler as A4) at 3000lbs Blidworth coal per hour. To my eyes they are all 73%. If we asume that mass of Belpaires are higher than round tops it is vanity. B1,Halls and Black Fives had also identical boiler efficiencies if I remember OK. I do not have the Hall and Black Five reports anymore. Some good Pacifics had round firebox covers. History has proved that if You must have more than two cylinders for mechanical balance at speed or gauge, three is a good number and inside cylinder drive to front big wheel shaft is good. You were getting very close Thompson. It is therefore strange that he opted for having outside cylinders hanging in the middle of nowhere as he could not reuse the Darlington cast monoblock cylinders from the P2 for clearence reasons. We can with the benefit of hindsigth and Hornbys phantastic gift to humanty help him.

It is my ambition to show mr Thompson how he should have rebuilt the 2-8-2 thing of mr Gresley that by the way had better been a 4-8-0 based on a 2-10-0 with round top boiler. Full size is out of question going through the heavenly doors so 1:76 will have to do. I am therefore looking for a model of A2/2 and Evenings star that can serve. Asking mr Wright to modify will probably not work and funds are not unlimited either. There is a DJH kit of A2/2 on ebay but question is how long before the Hornby thing is for sale and what would be easier to modify? Will the top of the model (round topped boiler) be sold separately?

Good try 2-12-4 tank with long life

Around ww1 civil engineers began to understand and could calculate the rail disturbing forces from steam locomotives. The 47xx had ca nine tons on each driver. It had very short connecting rod driving second driver. Pulling hard forward this means that the driven wheel will be pushed downward with further 6 tons and the two neigbouring wheels will unload three tons each when piston is midway.Going backward we are getting close to wheel lifting and that is a no-no. The cure had been to drive onto third axle like everywhere else with 2-8-0s but this would have been very long connecting rods and considered unsafe at the time.

Deleted

If Holcroft and Jarvis had been in charge and started with the 9f it can maybe interes some hove ofsprings could have looked. A three cylinder compound 4-8-0 can do anything a Pacific will do and burn less coal and for smaller jobs a 4-6-0 with either three or two compound cylinders

Hello Corbs Thank You for asking. If it give some figures and analyses like the old BR steam test reports it will be very interesting for an old steam dreamer. I hope it is not considered confidential but can easily understand and accept if it is.

Thank You Corbs for saving my day. In the interview it is mentioned that a test report was made for the 101,6mph test. Can that be had by the public? A new numerical model run Total train length 190meter making 1420 kW heating of air Total train mass 485000kg making 347 kW oil and rail heating total demand on locomotive 2400 indicated horsepower. We asume that an A1 can do 31410 lbs of steam per hour from 4260 lbs of coal showelled by two firemen. This is the One hour figure from mr Cox/Britania. A V2 used 13.2lbs at best opperating condition and gives 2400 ihp on Tornado if it steams as well as a BR7. The continious 3000lbs/h coal showelled by one unionized fireman makes 24000 lbs steam per hour or ca1800 indicated horsepower. A drag plate area of 0.13squaremeter per meter train and a rolling resistance coefficient 0f 0,0015 gives reasonable estimates of steam train speed possible. Thank You for reading

The simple numerical indicated horsepower for steam locomotives at steady speed calculator functions quite well . The Tornado train did 45,4meter per second. Train was 210m long including Tornado and 67 Train mass was 573 tons all inclusive. Rolling takes 385kW Disturbing air takes 1570kW or 2650 indicated horsepower. Maximum steady ihp for a V2 on test plant was 1990 ihp A Britania gave2200 ihp on rollers and a LMS pacific 2550. One can use more steam than max steady evaporation rate but pressure goes down fast. Tornado did not run 101,6 mph for many minutes so it is not unrealistic that Tornado ca do 2650 ihp for a short while. The LMS calculated over 3200 ihp when they measured 2511 drawbar horsepower in a short burst. The difference between drawbar horsepower and indicated was asumed to be machine friction,locomotive rolling resistance and locomotive air resistance. I find it more simple to se most of it as total train air resistance. Indicated horsepower steam demand and boiler evaporation are simple to calculate. This method can be used on electric or diesel trains as well. Total train length in m mutiplied by 0,13 (UK normal gauge) 0.15(Berne Gauge) 0.17(US) gives flat plate area in square meters This shall be multipled by 0.5 *air density(1,23kg/m**3)*Velocity cubed and giv ve Watts for airwork. Total train mass (kg)*gravity*0.0015*velocity gives rolling work in Watt

Damned. My simple power model shot down in flames But thank You for answering

Was it draging or pushing?

Was it diesel supported?

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.

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.

Or my 0.18squaremeter drag-flat-plate-area per trainmeter is to big. The former Mallard calculation gave also very high horsepower values.

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.

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.

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?