A six-year overhaul of Gresley N2 Class No. 1744 is nearing completion, and passed its steam test in August, with a return to service planned for next spring.

No. 1744 is the oldest surviving locomotive designed by Sir Nigel Gresley, and is being overhauled at the workshops of the North Norfolk Railway at Weybourne.

Withdrawn from service for overhaul in late 2018, that has proved to be considerably more extensive and costly than expected. The overhaul began in 2019, but both timescales and costs were impacted by the COVID-19 lockdown and the war in Ukraine.

After 1744 was stripped down, it was soon obvious that considerably more work was required than expected. This has led to extensive mechanical and boiler work, culminating in a final overhaul cost of around £650,000.

It was in mid-December 2024 that 1744 arrived at the North Norfolk Railway. Since then, the two carbon steel steam pipes from the superheater header to the steam chests have successfully undergone non-destructive testing and examination, all the historic welds have undergone magnetic particle inspection, and the thickness of the pipe wall was measured with an ultrasonic thickness gauge.

A hydraulic pressure test was carried out after clamping the two pipes together to form a single unit, then subjecting it to a hydraulic pressure test of 255psi, equivalent to 1.5 times the boiler’s safe working pressure.

Seventeen new washout plugs that have already been procured will now be fitted to the boiler; the superheater header is being prepared for hydraulic testing to 255psi, and all the lubrication pipework and fittings are being prepared for fitting to the locomotive during its reassembly.

Once everything has been reassembled, a final hydraulic pressure test of the boiler will be carried out, which will mark the start of the boiler’s ten-year boiler certificate.

The overhaul is initially being funded by the North Norfolk Railway, with the cost being recovered later through operation of the locomotive for a period without charge, although there is still a substantial funding shortfall to meet the final overhaul cost. To meet this cost, the Gresley Society has launched The N2 Overhaul Completion Club to raise £100,000, with 100 people each donating £1,000 in up to eight instalments.