The major components for the new boiler were made at quite an early stage, as part of what proved to be an abortive contract for its manufacture by the now defunct firm of Winson Engineering. These parts and were moved to Dinas in Spring 2000, together with the condemned original firebox. and other remaining parts. From left to right, the parts seen below are the (condemned) old firebox, the new steam dome, new boiler barrel, and new inner and outer firebox wrappers.

The old components subsequently moved to the FR's "Boiler Park" exhibit at Minffordd, whereas the new ones are now a part of the loco. The old boiler barrel was scrapped at Tyseley.

The design for K1's all-welded boiler was approved for production by the insurers in early April 2001. The contract to assemble the boiler was let to Israel Newton & Sons of Bradford. This is the same firm which has built new boilers for other Edwardian products of Beyer Peacock, namely The Earl and The Countess at the Welshpool & Llanfair Light Railway.

The pictures below (credit: Robin Rees-Jones) were taken during a visit to the works of Israel Newton at Idle, Bradford, on December 12th 2001.

The following pictures of K1's boiler under construction in Bradford (also by Robin Rees-Jones) show progress by March 21st 2002. They show the assembly of barrel, outer firebox and front tubeplate essentially complete; it will be noted that the smokebox forms an integral part of the boiler barrel, rather than a separate component. The inner firebox was in the process of being welded up prior to being located in the outer wrapper for marking up and drilling for stays. Tube holes were being drilled in the rear tubeplate, i.e. the forward surface of the inner firebox.

The new boiler passed its hydraulic test (i.e. testing the boiler with water pressurised to well above the working steam pressure) at Israel Newton's works on August 8th. This left just a few days' work for Newton's (fitting the foam plate and steam collection pipes) prior to transportation to Boston Lodge. Paul Lewin's pictures below show the completed boiler being tested with dye penetrant.

The completed new boiler arrived at Boston Lodge on the morning of August 15th 2002, and was unloaded in the yard. The K1 Group working party on the following weekend started work preparing the boiler for its steam test and fitment to the locomotive. Andy Rutter's pictures below show (left to right) John Startin and Charles McKenzie levelling the boiler, Colin Hill attaching the chimney (which originated on K2, and had been in use as a fund collecting box), and WHRS Chairman Dave Kent checking it for level.

The preliminary steam test took place successfully on Sunday September 15th 2002, with a view to a formal test and inspection soon afterwards for the insurer's Inspecting Engineer.

The new boiler passed its official steam test on October 7th 2002, as seen in Andy Rutter's pictures below.

The boiler was lifted into the frames on Friday October 11th, followed by the cab.