Subway is one of several "LP games" released some time in the 80s, where the "box" is the shape and size of a record sleeve and folds out to reveal the board.
This game is a tafl derivative (see Hnefatafl) where one player controls 1 mother submarine and 8 mini subs, while the other controls 16 destroyers. The goal for the sub player is to escape the board with the mother sub, while the other player tries to eliminate it.
There are a few differences from the usual tafl beside the obvious elongated playing field. By default, pieces can only move one step at a time; rook movement is an optional rule. Some tiles allow the submarine player to photograph "defense installations", which forces the other player to remove a destroyer from the board. At some points around the edges of the board it's possible (rather arbitrarily) to move diagonally.