You will be relieved to hear that this is not an extant subway access to Cathcart station, but one which was bricked up many years ago. A conveniently removed brick allowed the photo. I don't know why this eastern entrance, on Old Castle Road, was closed. Other comparable Cathcart Lines stations still have entrances at both ends.
Company: Cathcart District Railway
Photographer: David Panton
Make contact: David Panton
Image number: 64989