This signal box was on the north side of the line east of Saltcoats controlling access to the Auchenharvie Colliery pits.
The pits had previously been served by the Ardrossan Waggonway.
Going east, on the south side of the line a siding (on the course of the waggoway) ran east to Auchenharvie Daylight Mine (where the coal was brought up from the colliery), Auchenharvie Colliery Pit No 5, Ardeer Iron Works and Ardeer Chemical Works.
On the north side a line ran north east to Auchenharvie Colliery Pit No 2, west to Auchenharvie Colliery Pit No 1, north (passing under the Lanarkshire and Ayrshire Railway to Auchenharvie Brick Works and Auchenharvie Colliery Pit No 4.
The colliery closed down in 1915. The box closed in 1934. The main line remains open.