Having previously built a 7 1/4 inch gauge A4 "Sir Nigel Gresley", the A1 in 5 inch gauge followed. Designed by Peppercorn just after the war, the A1s featured three sets of Walschaerts valve gear, rather than using the Gresley-Holcroft conjugated gear with its derived motion for the middle cylinder.
Work to date is to a high standard. The locomotive chassis is complete, including draincocks and compensated brake gear - silky smooth to turn over, it looks to have been run in on air for some hours; driving wheelsets run in prototypically correct split bronze axlesboxes.
The combustion chamber boiler is exceptionally well made, neatly flanged and with good solder penetration throughout, firebox is bushed for a fusible plug. The backhead has water gauge fittings, clack valves and regulator; a pair of spring type safety valves are fitted.
The tender chassis is largely complete, the tank is part-built in brass, with a pack of profiled brass for the cab.
Complete with 24 sheets of drawings.
Despite efforts to save 60145 "St Mungo" - then only 17 years old - all 49 of the original class were scrapped by 1966. In 2008 a 50th locomotive of the class - 60163 "Tornado" - was completed at Darlington.
gauge | 5 inch |
length/inches | 50 + 28 |
width/inches | 10 |
height/inches | 15 |
bore x stroke/inches | 1 11/16 x 2 5/16 |
wheel material | cast iron, 7 3/8 inch diameter |
axlebox type | split bronze |
cylinder material | 3 x cast iron |
valve type | piston |
valve gear | 3 x Walschaerts |
reverser type | screw |
boiler maker | P Beeby |
boiler type | locomotive with combustion chamber |
boiler material | copper |
boiler construction | silver soldered |
fusible plug | yes |
safety valve(s) | 2 |
safety valve type | spring |