This double track tunnel originally ran from Kelvinhaugh Signal Box to the west to Stobcross station to the east. It closed in 1965. The original tunnel is 755 yds long.
The tunnel was partially re-opened in 1979 - the east portion being reused and a short new single track tunnel being built west to near Finnieston West Junction, the western portal being at roughly the site of the Kelvinhaugh Refuse Despatch Works.