The Cavan and Leitrim Railway gains its name from the counties through which it ran and was promoted to provide both a passenger service for what is even today a sparsely populated area and to help exploit the mineral deposits in the hills above Lough Allen, just over the county border of Roscommon. These comprised coal seams in the hillsides around Arigna. The principal route ran westwards from the Great Northern Railway (Ireland) branch terminus at Belturbet to the railway's headquarters at Ballinamore before turning southwards to its terminus at Dromod, where it met the Midland Great Western Railway.

While the 'main line' ran almost exclusively on its own formation, a branch continued westwards from Ballinamore and followed local roads for most of its routes. This, the 'tramway' as it was always known, skirted the southern slopes of Slieve an Ierin, crossed the River Shannon and terminated at Arigna. A freight line continued on from a trailing junction just outside Arigna station up into the surrounding hills. The coal traffic which the tramway generated soon became the railway's most important business, this being Ireland's only important source of the fuel. In addition, seasonal cattle traffic was important, helping to supplement what was always a comparatively light passenger demand.

Rural throughout its length, the railway's works were at Ballinamore but, after its amalgamation into the Great Southern Railway after the formation of the Irish Republic, repairs and maintenance beyond the most trivial were conducted elsewhere. Coal traffic kept the railway open long after passenger and other freight receipts had radically declined but, when this was replaced by imports, the Cavan and Leitrim quickly succumbed.

Today, some of the C&L's buildings remain - Ballinamore station is now a school - and, at Dromod, part of the line has been re-opened as a preserved tourist line centred on a beautifully restored terminus station and loco shed to which new carriage sheds and other facilities have been added.

The best introduction to the railway's history is P J Flanagan's The Cavan & Leitrim Railway, first published in 1966 by David and Charles of Newton Abbot. Although out of print it is well worth hunting up a copy.