One of the first challenges has been to repair the teak frame of the carriage; and undo the damage caused by many decades of human use and exposure to the elements. Surprisingly, in spite of being a timber frame, most of the damage has been caused by rust.
In the 1890s, the normal way to construct the wooden framework of a railway carriage was to use traditional joints such as ‘mortise and tenon’ and ‘lap joints’. In the absence of any effective glue, steel woodscrews were used to keep these joints together. Where further reinforcement was required steel brackets were added, held in place by bolts or coachscrews. Over time these steel screws and bolts have rusted, and as they rusted they have caused considerable damage.
As the screws and bolts slowly rusted, the expanding corrosion inexorably forced the wood apart, bending and splitting it. In some places, such as the tops of the corner posts, the fixings have split and splayed the timber in every possible direction.
To repair this sort of damage, the rusty fixings must first be carefully removed, the splits stabilised, holes plugged, and finally the surface replaced with a structural veneer of sound material. Once complete, the repair will be visually unobtrusive and should last for many years.
The above information was kindly provided by David Gunn, a Festiniog Railway craftsman working on the restoration of Met 353.