The line was built for the Royal Flying Corps to facilitate the movement of building materials, stores, possibly workers, etc.

Members of the Royal Defence Corps and the McAlpine's workers travelled in to Loch Doon daily from Ayr by train.

The proposed 1,150 foot or 350 metre tunnel to take the railway to the lochside was never built and the plan for its construction at a cost of £150,000[5] led to an analysis by the Director of Fortifications and Works that ultimately resulted in the cancellation of the entire gunnery school scheme.

The line was standard gauge and branched off the Dalmellington line about 200 metres northwest of Dalmellington railway station,[6] crossed Ayr Road, crossed the Muck Water by a bridge (NS474059) and then ran parallel to the Craigengillan driveway before turning south-east and running up to near Dalfarson (NS479025) where a 5 metre long platform was built,[7] together with a water tower and coaling dock for the steam locomotives.

[7] A letter written on 7 January 1918 by the Air Board however stated that the railway had actually been built on the Craigengillan driveway itself and its removal would be straightforward.

[13] A monorail was built along a section of the east bank of the loch as witnessed by the row of large concrete blocks that are still present and visible when the water is low.

[17] It is not known when the railway was lifted, however it is on record that the scheme was simply abandoned until at a date well after the end of the war when it was discovered that the agreement with land owners was that the site should be returned to its original condition.