The 563 Locomotive Group has issued a report on progress to restore to operational service T9 Class 4-4-0 No. 30120, formerly London & South Western Railway No. 120, in time for its 130th birthday in 2029.

Work has been contracted to the Flour Mill near Lydney in Gloucestershire, where they have started disassembling the T9 so that the locomotive and tender can be inspected and assessed for work required before 120 can return to steam.

That is expected to take three months, and although no major problems are expected, the group considers it prudent to understand the condition of major components and produce a budget before work starts.

Inspection and assessment will be conducted in conjunction with the National Railway Museum, and will focus on two main areas of interest: the boiler and the cylinder block.

The boiler is a pressure vessel, and is usually the single most expensive part of any steam locomotive, so a decision where to overhaul a locomotive often depends on the amount of work that needs to be done.

The locomotive was originally withdrawn from service because of leaking stays, but only time will tell whether there is any reason to be unduly concerned.

However, the cylinder block is a known problem, as during its last period in service at the Swanage Railway, it received a stitched repair. It is important to ensure the cylinder doesn’t have another failure during its next ten-year ticket.

The Swanage Railway has a copy of the drawings for the cylinder block, so there is only the need to get new patterns made, and a block cast, machined, and fitted. Interestingly, the T9 Class used the same pattern cylinder block as the M7 Class and the Drummond 700 Class, also known as ‘Black Motors’.

After a new block has been cast, before it can be machined and installed, it must be allowed to ‘weather’ for a time to allow the crystalline structures in the cast iron to develop properly.

For this reason, the Trust wants to get a new block cast as soon as possible in case the block needs replacing so that the weathering process does not hold up the restoration.

Before any work can start, however, it will all be subject to completing an overall assessment of the locomotive and obtaining an agreement from the National Railway Museum to continue with the overhaul.

Because prices can vary a lot and the Trust is not yet ready to place an order, The Trust does not yet have a formal quote., although judging by the cost for other projects, it will cost approximately £50,000 to manufacture the patterns and cast the new cylinder block.

There will also be additional costs for machining and fitting, but although they aren’t cheap, the original cost is considerably less than originally envisaged.

The Flour Mill has confirmed that in early December the boiler was successfully removed from the frames, and is now ready for a comprehensive inspection and assessment of its condition.

Thanks to an agreement between the National Railway Museum and the Swanage Railway Trust, 120 will remain at the Swanage Railway for an extended stay.