Singapore's first MRT system, the North-South and East-West Lines (NSEWL), will hit the age of 30 next year.
To renew its ageing infrastructure and extend the system's lifespan, a slew of projects are under way, including the installation of a new signalling system to allow trains to arrive at shorter intervals and the replacement of the power-supplying third rail.
Last Tuesday, a massive four-year project to replace 188,000 worn-out timber sleepers with new and hardier concrete ones was completed.
For commuters, this means a speedier, smoother and safer journey. Sleepers help to hold the tracks in place, and worn-out ones can lead to a bumpier ride.
During the project, speed restrictions were temporarily imposed where the new sleepers were laid, thus increasing train journey times.
To give its workers more time during off-service hours, operator SMRT also ended services earlier for some time, and opened certain stations later on Sundays.
This inevitably affected the travel plans of commuters.
The replacement of 96,000 sleepers on the North-South Line and 92,000 of them on the East-West Line marks a milestone in their renewal.
With one major item on the list checked, the Land Transport Authority and SMRT can continue to roll ahead with the other upgrading projects.
Rail engineers typically have a short working window - between three and four hours in the early morning - when train services are offline.
It is a tight window, bearing in mind that tracks and trains have to be ready for commuter service right after. With the sleeper replacement project now laid to rest, more time will be freed up for the remaining upgrading works.
Rail engineers will also have more resources with which to diagnose and find solutions to other potential problems that could ail the ageing NSEWL, and boost the reliability of the island's most-used lines.