A map of the railway

The Arlesdale Railway, also called the "Small Railway", is a 15"-gauge railway running from Arlesburgh along the old route of the Mid Sodor Railway toArlesdale. At Arlesburgh, connections can be made between it and the Arlesburgh branch. The line is mainly used to transport waste materials from several of the abandoned mines at Arlesdale for use as ballast, but it also attracts popularity due to the novelty of being pulled by a 1/3 scale engine.

From Arlesburgh the line stops at Arlesburgh Bridge StreetFfarquhar RoadMarthwaite, and Arlesdale Green before turning south to Arlesdale.

The ownership of this railway is shared by the Small Controller and the Owner of the Skarloey Railway.

The Arlesdale Railway appeared in Small Railway EnginesOliver the Western EngineDuke the Lost Engine,Jock the New EngineWilbert the Forest Engine, and is mentioned in Thomas and his Friends. It also appeared in various annuals and Railway Series related books. It did not appear in the television series, however, some of the engines were made in a few merchandise lines.   

The Arlesdale Railway have not made any appearance in the magazines. However, the magazine story, The Tiny Engine, features a miniature railway which may be the Arlesdale Railway. There is also another narrow gauge branch line alongside Duck's Branch Line, run by a saddle tank engine named, Sidney.

The Ravenglass and Eskdale Railway is the real counterpart of it.

In the CGI series, the Maron-Arlesburgh Branch Line follows this line.