A Prototypical Space Saving Idea called a Sliding Platform Bridge

[Bigmac]

i would imagine many members are aware of the procedure at Ventnor I o Wight staiton--( from wikepedia):

The station had a platform connected to the station buildings and a narrow island platform. There was only one track between the side platform and the island platform. When this track was occupied, an incoming train arrived at the outer face of the island platform and passengers had to pass through the train on the inner track. When this train then departed, a temporary bridge that was a former ship's gangway, as used on the Portsmouth to Ryde ferries was manually pushed across the intervening track to allow passenger access to the train on the outside of the island platform. Further away from the station buildings were goods sidings which mainly served coal merchants who operated from caves in the chalk sides of the station cutting.