The proper maintenance of railway tunnels is very important from the point of view of the safety of the trains as well as that of the travelling public. In order to ensure that the railway tunnel is in a good condition all year around, it is inspected in the following ways.
Inspection by assistant engineer Apart from routine inspection, the tunnel is inspected in detail by the AEN once a year before the onset of the monsoons. All the substructures of the tunnel are inspected and the aspects that require attention are recorded.
Inspection by permanent way inspector The PWI inspects, the tunnel in detail once in a year after the monsoons are over, paying particular attention to the track and its components. The aspects requiring attention are taken care of immediately.
Inspection by works inspector The structural portion of the tunnel is inspected in detail once in a year by the IOW. All the sub-components of the structure are examined in detail. The parts requiring attention are attended to in a planned way.
Details of a Tunnel Inspection
The following features of a tunnel require detailed inspection and examination.
Portal at either end This is inspected to ascertain whether there are any signs of slips in the slopes above the portals or whether the masonry is in any way cracked, shaken, or bulging, or whether there are any apparent signs of movement.
Section of tunnel in relation to moving dimensions This inspection is done to check if the section, whether on straight routes or curves, conforms to the schedule of dimensions.
Tunnel walls and roofing These are inspected in the case of lined tunnels to ascertain whether the lining is in a satisfactory condition. Doubtful places, such as loose projections, should be tapped to check for hollow sound or loose rock.
Drainage This is inspected to ascertain whether the side drains are adequate and functional.
Ventilation shafts These are inspected to ascertain whether the ventilation shafts are adequate and free from vegetation and other growth.
Lighting equipment and special tools This inspection of these features is required to ascertain whether the lighting equipment and special tools, wherever supplied, are in a good state.
Track The track is inspected to ascertain whether its line and level are correct, including that of the approaches. Rails, sleepers, and fastenings should be particularly examined for corrosion.