Skarloey, a narrow gauge saddle tank engine, is the oldest engine on the Skarloey Railway. Talyllyn, from the Talyllyn Railway, is his twin and Rheneas is his brother.

Skarloey is the sage of the Skarloey Railway and is an old, faithful little engine. Although once full of enthusiasm and his own ideas in his youth, Skarloey is now one of the oldest engines on the Island. He is a calm-natured, quaint and mature engine and may often try to guide or watch over less experienced narrow gauge engines in his firm but fair and friendly manner. He acts kindly to engines and passengers alike and always enjoys a gentle, smooth journey through the woods by the lakeside and stopping at all the gates and stiles he remembers so well.