Ventilation, Lighting and Drainage
Explosive charges and plying of vehicles or locomotive for moving drilling equipment or for mucking leave fumes and unhealthy gases inside the tunnel. An efficient ventilation system to drive away these fumes and gases from the tunnel should be provided for all tunnels during construction. Lighting requirements may be considered temporary during construction of the tunnel and permanent for the tunnel in service. Tunnel lighting during construction is a complicated process as there is need to introduce lighting arrangements at the time of drilling and charging of the holes, and then withdraw it prior to blasting. Most short-length railway tunnels, especially those in remote areas where power supply is difficult to obtain, are not lighted permanently. Inside the tunnel a suitable drainage arrangement should be provided so that the water collected can be drained without flowing over the surface of the road or track.