Forty years experience club running a 7 1/4 inch gauge LNER A3 "Flying Scotsman", bought from Walter Harper (of "Flying Dutchman" fame) in 1971, informed the builder's ideas when it came to setting out a design for the Royal Scot - in particular plenty of adhesive weight for traction and generous full gear cutoff for reliable starting on heavy trains.
After running for ten years, the engine was overhauled over winter 2020 - with the boiler off the frames, the opportunity was taken to retube it, although the original tubes removed had remained in excellent condition (and could probably have done another ten years judging by their condition). The boiler had a twice working pressure shell test at this time, it's recently had hydraulic and steam test following reassembly.
Other work included repainting and varnishing the engine and minor modifications to improve access to the grate and ashpan - the engine is now "ready for the next ten years" according to the builder. Having steamed it earlier in the week for the first time since its overhaul, we couldn't disagree - the engine is in first class order.
Built as a two cylinder engine, the cylinders are of similar proportion to Martin Evans' "Highlander" design, with larger ports and 3/16" lap; the pistons and valves are fitted with Clupet rings. The engine steams freely and runs exceptionally well with well-defined exhaust beats, notching up nearly to mid gear in either direction - there's some video of it running here.
Complete with a pair of purpose built stands.
gauge | 7 1/4 inch |
length/inches | 64+38 |
width/inches | 14 |
height/inches | 20 |
wheel material | cast iron |
axlebox type | plain bearing |
cylinder material | cast iron |
valve type | piston |
valve gear | Walschaerts |
reverser type | screw |
lubricator type | mechanical |
injector(s) | 2 |
boiler number | LB-318-02 |
year built | 2002 |
boiler maker | Holt |
CE mark | n/a - pre-2002 |
working pressure/psi | 100 |
boiler type | locomotive |
boiler material | steel, copper tubes |
boiler construction | welded, expanded tubes |
hydraulic test valid to | 28/Apr/23 |
steam test valid to | 4/Jul/22 |
superheater(s) | 0 |
fusible plug | yes |
safety valve(s) | 2 |
safety valve type | pop |
whistle | yes |