Volunteers at the Corris Railway have started the ten-year overhaul of the railway’s steam locomotive No. 7, a replica of the Talyllyn Railway’s Kerr Stuart “Tattoo” class locomotive No. 4 Edward Thomas.

This year is No. 7’s twentieth year of service on the railway and the second time it has had a major ten-year overhaul, following the expiry of its boiler ticket at the end of last year’s running season.

Since its last major overhaul, No. 7 has been a regular performer, but in December 2018 it was taken out of service after a lack of lubrication caused a section of the valve gear on the driver’s side to seize.

It was taken out of traffic immediately, and with the help from the Vale of Rheidol Railway, repairs were completed before passenger train services started again in 2019.

A second failure occurred during last year’s gala when a steam gasket failed after working the initial double-header with steam locomotive No. 10 Falcon.

Since its last major overhaul, No. 7 has clocked up nearly 4,000 miles, which includes several hundred miles working on the Talyllyn Railway from Tywyn to Nant Gwernol.

During Christmas and New Year, volunteers removed the saddle tank, cab, coal bunker, boiler cladding, steam fittings, pipes, and motion. These have been stored indoors on a flat wagon so that work can continue on the boiler and smoke box.

After the boiler has been lifted from the frames, it will be re-tubed at Maespoeth before being inspected to ensure it meets the necessary safety requirements to receive certification for the next ten years.

The driving wheels and pony truck will also be removed to provide access to the frames so they can be cleaned down and repainted.

A new stainless steel smokebox will be fabricated by the Vale of Rheidol Railway, who will also re-profile the tyres and fit new crank pins.

New bearings for the driving axles will be produced in the Corris Railway’s refurbished machine shop at Maespoeth, where a recently acquired Huron mill will be used to digitally measure the axle centres and motion to an accuracy of three decimal places.

The railway usually derives much-needed income from its Santa Specials, which this year was due to feature new-build No. 10 Falcon, but they had to be cancelled this year because of the devastating consequences of storm Darragh.