Lift Rope

Cable to vertically connect the stations. When fully connected, lift can be used.
Overview
Lift Rope is a building used to connect Lift Stations to one another. It functions as a vertical traversal aid, and it can also be used like a 

Because of that flexibility, Lift Rope is useful when preparing a route in advance or when extending access through a shaft before the full Lift Station network is completed. It provides immediate movement support while also serving as the infrastructure that lets Lift Stations link together once they are installed.
Official description
Cable to vertically connect the stations. When fully connected, lift can be used.