71000 Duke Of Gloucester, The Devonian

71000 breaking records on Whiteball and Dainton.

Category:

Autos & Vehicles

Tags:

• steam
• 71000
• duke
• gloucester
• south
• devon

[officem01]

Came on this by change. Great to see that UK rail is using steam engines again on some of its express trains. Looks like that engine is going mighty fast up those hills sorta like a high speed train. I'd hardly call that chuffing along. Sounds powerful.

[tokzichemical]

my half grandad (derek) and his team restored this isnt it good it took em 5 years

[MorrisManDanceMan]

brilliant video thanks for putting in on 

[CoeurDeLoin]

@hiyadroogs Indeed. Typical values are from 0.35-0.5 (Wikipedia). 0.25 is a rule of thumb used for design. Assume a higher value and you may have problems in poor conditions. Another factor is weight distribution. Churchward built only one Pacific before settling on 4-6-0 as best on inclines. But if weight is not limiting, you can just pile it on, like a Big Boy 2-8-8-2, which needed 135000lb TE for coal and ore trains over the Rockies.

[hiyadroogs]

@CoeurDeLoin Thank you for that information. I would think that coefficient of friction would also be a necessary parameter in the calculation, & would vary widely between wet rail, dry rail, & with the sanding gear on.

[CoeurDeLoin]

@hiyadroogs Power=TE*Speed. With TE in pounds, speed in mph, divide by 375 to get HP. Your 9F would be pulling 22500lb at the drawbar.

TE is usually quoted based on pressure + cylinder and crank geometry, and tends to over-estimate. Locos are usually designed to 25% friction, so this is achieved with only 40 tons on driving wheels. At 22.5 tons per axle, a King could only deliver 37800lb at the drawbar, yet was rated at 40300. GWR engines were never beaten on efficiency (HP/ton coal) though.

[hiyadroogs]

Thank you Moochy! Glad to be of some help to you. It's great that you have taken an interest in these magnificent machines. They are only kept running by the dedicated hard work of new generations of enthusiasts. There are plenty of preserved steam railway lines around the country, why not take a trip to one, & ask the drivers or firemen to explain their workings. They'll be only too happy to invite you into the cab & show you around! : )

[moochykins]

wow!!! what drew me towards this loco was reading about tornado's construction and that someone had plans for the a1 to achieve 120mph but it was snubbed due to this loco's failure during br service. you know alot about steam dude!! the technicalities you speek of baffle me!! will keep an eye out for any other comments you post.

[hiyadroogs]

D of G has smaller driving wheels than a Duchess or an A4. The speed limit for steam engines is largely determined by how quickly steam can get in & out of the cylinders with the minimum of resistance to flow. British Caprotti valve gear is the best way to achieve this, but her smaller diameter driving wheels (6'2") limit the advantage slightly as far as ultimate speed is concerned. I believe the Duchess & A4 are 6'9" in diameter.

[hiyadroogs]

This is difficult to assess. In BR service, the Duke was plaiged with flawed construction problems which caused very poor steaming. She never remotely approached her true potential in BR paaenger service. Many modifications to her original specifications have been made to her boiler, firebox, exhaust, & valve gear. Recently, a modification was made to one of the cylinders which has liberated even more power! Her free steaming valve gear & boiler should see her exceed 115 mph comfortably.