In the 25 years since the restoration project began, the rolling stock has increased significantly. The current loco/carriage shed, despite the recent temporary expansion, has proved to be inadequate to serve as a workshop and to safely store the current rolling stock. It was therefore decided to expand the storage facilities at Lhen Coan and planning permission was submitted to the Isle of Man Government in February for the 'construction of a replica of the original alignment, but extended to two tracks to provide workshop facilities'. Since approval, the team has worked quickly to install the new structure between Lhen Coan station and the existing loco/carriage shed (incorporating the site of the siding where Sea Lion languished for many years after the Second World War). A section of earth banking was excavated and one lime tree was felled. The foundations were laid by the volunteers who worked hard to prepare the site for the construction. Bringing in the materials for the new structure was difficult as the railway is in such a remote inaccessible location, but as usual the volunteers rose to the challenge.

The new structure is based upon the latter day GGR engine shed in the days before the line closed in 1962. The construction is ACQ treated weatherboard with a slated roof and features a concrete floor and service pit, together with workshop facilities. It is 9 metres long, 4.8 metres wide and 4.03 metres high. It contains two sets of double doors over the trackwork plus a further single door at the Lime Kiln end for access. Dummy windows consisting of three panes were cut into the wall facing the main line.

The existing shed will be used for the carriages while the new structure will house the engines.