 During construction a shaft located at the midpoint of the tunnel was used to speed up work, as it provided another two working faces for the roadheaders used.The shaft is today used for ventilation and emergency egress, in addition to a pedestrian tunnel that parallels the eastern part of the tunnel.Eight cross passages link the main and emergency tunnels, two more cross connects provide an emergency exit to the Domain Tunnel, and two emergency refuges are also located in the tunnel.