Boiler – 2004 saw the launch of the Trust’s £500,000 bond issue to finance the construction of the boiler and complete the locomotive. Following a very good initial response and uptake of bonds it was announced that the Trust had chosen Dampflokwerk Meiningen (Steam Locomotive Works Meiningen), a workshop of the Deutsche Bahn (the German Federal Railway) and through its subsidiary DB Fahrzeuginstandhaltung GmbH (DB Rolling Stock Maintenance Company), as the supplier for the boiler and associated equipment for the new locomotive. This decision came as the culmination of almost three years of exhaustive discussions with a number of possible suppliers in the UK and continental Europe as well as with the authorities on certification and quality matters. The final design would be classified Diagram 118a and would be coal-fired with a steel firebox and all-welded barrel. Meiningen would be able to design, build and fully certify the boiler to current EU safety standards and this homologation was an important factor in selecting the company for the boiler’s construction.
Motion – The Trust could announce that No. 60163 Tornado was now a Pacific following the fitting of all four coupling rods to its six 6ft 8in driving wheels (the name Pacific refers to the 4-6-2 wheel arrangement under the Whyte Notation of steam locomotive wheel arrangements) which now rotated freely together for the first time. Each of the four 7ft 6in rods weighs around two hundredweight and after forging, extensive machining and heat treatment, the four cost around £22,000 to manufacture. These rods are vital components within the £150,000 valve gear and motion assemblies, which were now the focus of work on Tornado at the Trust’s Darlington Locomotive Works.
The Trust also started work on the fitting of the rest of the outside motion. The bushes for the connecting rods were machined at Ian Howitt Ltd, Wakefield and one side of the locomotive had now been fitted with a mock-up of parts of its valve gear. This was to enable accurate measurements to be taken to set the length of the eccentric rod as the traditional method of heating the rod to stretch/shrink it used when the original Peppercorn A1s were built in 1948/9 is no longer recommended as it can affect the rod’s metallurgical properties.
Cylinders and valves – the six cast iron valve chest liners were cryogenically shrunk into the valve chests. The liners were machined slightly oversize, placed in a bath of liquid nitrogen and inserted – as they warmed up they expanded to become a tight fit.
Cab – the cab was returned from the North Yorkshire Moors Railway where it had been finally rivetted. The East Anglia Support Group provided the side windows and the bucket seats were made free of charge by the aircraft outfitters, Marshalls of Cambridge.