Whats Behind The Green Door?

First, apologies to Shakin Stevens. Hated the song anyway.
This is the front door of a disused house on Cuckoo Lane. I've been walking past it for years, and I've never seen it open. Even during the insanity of the property boom, this prime peice of real estate remained aloof, rejecting the suits of shallow developers, and, more unusually, teenage vandals. This door has never been kicked. It has just aged gracefully, like a beechwood dowager queen, for as long as I can remember. The house itself is right beside the long disused railway bridge and discontinued line, so maybe it was the Stationmasters house, and tickets of lading and passage were handed to now long -dead Baltinglaswegians, bearing sheep fleece to Dublin, or grain to Arthur Guinness in St James Gate, thro the little hatch in the middle. I just dont know, and I am loathe to ask the local historian (Hi Paul!)
Sometimes bald facts get in the way of a good story.
Any suggestions, Blippers?