The main line of the railway followed the route towards Johnstone shown in John Thomson's "Atlas of Scotland". From Ardrossan, the proposed line goes east through Saltcoats then to the south of Stevenston before turning north between Dubbs and Todhills to pass to the west of Kilwinning, where the railway terminated. The Doura mineral railway branch to collieries ran east from a junction north of Dubbs (Dubbs Junction) to a bridge across the River Garnock (at Dirrans), then turned northeast to serve a broad arc of collieries to the north of the grounds of Eglinton Castle. After passing Eglinton Colliery and Corsehill Head, the track turned east to a bridge over Lugton Water before a branch line north to the Fergushill colliery. The mineral railway continued southeast past Benslie pit then ended turning north to coal pits at Doura. The mineral line was later extended south to coal and fireclay workings at Perceton.