The railway is Northern Ireland's only standard gauge (i.e. full size) heritage railway and is based in the county town of Down.

Approximately three miles (4.8 km) of 1,600 mm (5 ft 3 in) Irish standard gauge track are open as of 2019, along which a steam locomotive, currently either O&K No. 1 or 3, and 1950s-60s era diesel locomotives are run, drawing preserved rolling stock.

Nestling under the shadow of the picturesque Down Cathedral, the railway currently operates through an Area of Outstanding Natural Beauty over approximately two miles of a restored section of the former Belfast and County Down Railway main line to Belfast out of Downpatrick to Inch Abbey, a ruined 12th Century Cistercian Abbey, with a further one mile built along the old Newcastle route to a Viking King's Grave, completing a triangle of track, which is hoped will be extended to the hamlet of Ballydugan three miles south of Downpatrick.

Staffed entirely by volunteers, the railway has been painstakingly rebuilt from nothing by people giving up their Wednesdays, Saturdays, Sundays or even Thursday evenings!

The Downpatrick & County Down Railway offers a number of exciting events for your enjoyment, or just to keep the kids busy! Trains run to Inch Abbey only on most operating days, with the exception of some special event days where trains may operate on both lines.