Maintaining our railways
Planned Network Maintenance
Train lines are used 24 hours a day, 365 days a year, so there’s not a time when the network isn’t being used, meaning from time to time works can cause bus replacements for passenger services.
We have a regular maintenance and renewal programme, which aims to improve the reliability of the Wellington commuter network. Work on the line which requires bus replacements are planned in advance, with the aim of keeping disruption to commuters to a minimum.
The majority of maintenance and upgrade work takes place at night or during weekends to avoid disrupting the thousands of passengers commuting in and out of Wellington on weekdays.
When we need to carry out major engineering work, such as replacing tracks or upgrading signalling systems, we may need to close a line or section of line for longer than 48 hours to complete the upgrade work efficiently and safely. For these larger scale works on the network we take advantage of the public holiday weekends at Easter, Queen’s Birthday, Labour Weekend and Christmas.
Typical types of work completed during planned bus replacements
The track is the entire structure that the trains travel along. It includes the rail, sleepers (support for the rails), and formation including the ballast (stones surrounding the sleepers and rail). The track also includes sets of points (moveable sections of track that allow trains to cross each other or move from one line to another) and level crossings (sections of the railway that the road passes through). During planned maintenance we can be replacing or repairing some of, or all of the track components. Points and level crossings are particularly complicated as they not only involve the track, but also the signalling system.
When parts of the track are replaced, they often require a settlement period. Temporary restrictions to the speed that services can travel at during these sections may be used to ensure the repaired or replaced section of track is safe for normal speed.
Signalling – The signalling system directs trains around the network safely, it also keeps them spaced apart to avoid collision.
The signalling system is the brain that drives the points which direct trains where to go and also activates level crossing alarms when a train is approaching. During a maintenance period staff can replace the mechanical or electrical parts of points and repair or replace signals components.
Traction – This is the overhead power source that provides the electrical power to the Matangi units around the Wellington region. This includes the structures that support the wire, the overhead wires themselves, and the substations along the rail corridor that supply the power. During work on the network, traction staff perform general maintenance, inspections and replace sections of overhead wire or the structures that support it.
Traction staff are also responsible for making sure the overhead power is switched off during major works.
Bridges & Tunnels – There are 60 bridges and 16 tunnels in the Wellington area. These vary in length from a few meters to the Remutaka tunnel which is 8.8km long, the second longest rail tunnel in New Zealand. During work on the network crews perform regular maintenance and inspections of these structures. During the longer maintenance periods bridge spans, sleepers and rail can be replaced, and strengthening can be carried out.