Frames – Following the completion of the optical alignment survey of the frames by staff from the Severn Valley Railway, the middle and rear cannon boxes for the driving wheels of the roller bearing- fitted locomotive were now in position. The front cannon box was in position by the end of June. The fitting involved working to clearances of less than 0.002in due to the roller bearings, compared with 0.02in on a conventional plain bearing locomotive. The coupling rods had their knuckle pin bushes machined and fitted; the fettling of one rod had been completed, with the other due to be completed by October. The forgings for the remainder of the motion, the valve gear, were also ordered. This included the eccentric rods, expansion links, radius rods, combination levers, union links and valve spindles.
Forging in progress at Hesketh’s foundry in Bury
The drop hammer is used to forge the coupling rods
Motion – the eccentrics (return) cranks, finished by Ufone, fitted the square spigots on the crank pins with no hand fettling. With the optical survey completed the drawing for the inside connecting rod could be finished, with the dimension for length corrected for the “growth” in the middle cylinder casting (one of the non-compliances). The reversing shaft bracket was fitted and the coupling and connecting rods polished. By the spring the expansion link brackets had been fitted to the frames. Work on reducing the height of the cab to the new Railtrack standard of 13ft continued and Darlington Locomotive Works now had a functioning Bridgeport milling machine. Considerable progress had also been made towards selecting a supplier for the boiler. As a part of the pre-qualification process, a visit to the locomotive works at Meiningen in Germany with the Trust’s VAB (vehicle acceptance body) took place in January and one was also organised to Interlok at Pila in Poland during July.
Engineering Link, the Trust’s VAB, paid a visit to Darlington Locomotive Works on 28 May 2002 as part of their on-going certification process for the locomotive. By late 2002 the rear steam chest covers (patterns, castings and machining) had been ordered from Kings Heath Patterns at Birmingham. Production of the ‘as built’ frame arrangement drawing on CAD was well underway to enable detailed stress calculations to be carried out on the frame modifications (two-piece to one-piece frames) as part of the certification process. The Matterson jacks and lifting beams were proof load tested to 25% overload as part of routine certification of lifting gear and a new lifting beam was ordered to attach to rear of engine to allow wheels to be rolled in under engine with a single lift .
A new structural floor over the offices at DLW was nearing completion. This would create a safe and dry storage area for the Trust’s patterns and allow space for a formally organised store at ground level for new components and for construction of other major components for the locomotive. By the October Convention in 2002 the locomotive’s frames had become a rolling chassis and 150 supporters of the project were treated to the sight of Tornado ‘moving’ for the first time!