The Island of Sodor: Its People, History and Railways makes mention of a 2ft. 3in. gauge mineral tramway connecting the mines at Cas-ny-Hawin to the port at Arlesburgh. At first the line was horse-worked but after seeing the success of the steam-powered Skarloey Railway in 1866, acquired an uncertain number of steam engines of its own.
After the tramway was bought by the committee of Peel Godred, they upgraded it to standards provided by the Board of Trade to allow regular passenger-carrying services, and eventually the tramway became part of the Mid Sodor Railway, and the Arlesdale Railway.
No descriptions were given about these engines, about how many of them there were or what eventually happened to them.
A possible engine of the tramway is Jennings from Awdry's MSR layout as the Fletcher Jennings class Bb was built in 1866 and the Arlesdale Tramway acquired its first steam engine in 1866.