These walls were intended to improve ventilation, as passing trains would push air forward, rather than to the sides of the tunnel. At the Atlantic Avenue–Barclays Center station, there is a wall between the two express tracks.
These walls were built to enhance air circulation within the tunnel, with the intention of guiding train-generated air flow towards the center rather than its sides. At the Atlantic Avenue–Barclays Center station, a wall separates the two express tracks.