Complex sentence: The station has 12 platforms which were enclosed by a 7 acre concrete slab, with the concourse and other buildings being built above them, escalators, stairs and lifts were provided to reach the platforms.
Split into simpler sentences: The station has 12 platforms which were enclosed by a 7 acre concrete slab, with the concourse and other buildings being built above them. Escalators, stairs and lifts were provided to reach the platforms.