SINGAPORE - Cracks invisible to the human eye can be detected by a rover used by SBS Transit for track maintenance on the Downtown Line (DTL).
As it moves over the rails, the rover provides real-time data to engineers on internal cracks or flaws in the tracks or any anomalies detected. It also monitors the tunnel itself, checking for cracks, water leaks or other structural anomalies.
Conceptualised in 2013 and put into service the following year, the rover has been upgraded over the years, including a major revamp in 2022 to add 3D cameras and laser sensors to allow it to inspect the third rail, which provides power to trains.
The latest version of the rail rover, which The Straits Times saw in action on Oct 10, was rolled out for use in March on the DTL. It will be deployed on the 22-year-old North East Line (NEL) at the end of 2026 or early 2027. The NEL has about 44km of tracks.
With rail reliability in the spotlight, and a
task force convened
to look into rail disruptions over the past few months, technological solutions such as the rover are vital to ensuring the system continues to work well without interruptions.
Track inspection can be a time-consuming and laborious task, SBS Transit said. Before the introduction of the rail rover, teams of two engineers had to physically inspect approximately 200m of tracks every night, using tools like vernier callipers to measure the alignment of the rail.
The rail rover can inspect around 4.5km of track per night with a team of three to four, reducing the time needed to inspect the entire line from nearly two years if done manually to 20 nights. The DTL has 84km of tracks.
SBS Transit said the rover is deployed twice a month on average, according to a maintenance schedule and other track work that needs to be done. The entire line is inspected over 12 months.
It detects an average of five anomalies on each deployment. This excludes the false positives, an issue its engineers are working to address.
SBS Transit said the rover has boosted maintenance productivity by 30 per cent, compared with its previous manual methods. The rover has also helped the operator collect data more accurately than if it is done by hand.
Mr Lee Yam Lim, chief executive of the operator's rail business and head of the DTL, said the rover helps to identify defects at an earlier stage. "We don't let the defects progress... where it gets worse and eventually comes to a point of no return," he said.
According to figures released by the Land Transport Authority on Oct 10, the DTL has in recent months suffered sharp drops in reliability.
It clocked 2.76 million train-km between delays that lasted more than five minutes as at August, dropping from 4.13 million train-km in July, although it remains the best-performing line on the MRT network since 2020.
Rail operator SMRT also uses technology to boost its maintenance regimen, having developed laser track trolleys to more efficiently assess the condition of rails over time, the curvature and evenness of tracks as well as the alignment of the third rail.
About 10km of tracks are assessed during engineering hours from 1.30am to 4.30am every night, with two trolleys being deployed.
This is more than double the 4km that six engineers can cover each night using handheld tools before these trolleys were in use in 2015, said SMRT during a media showcase at Bishan depot on Oct 9.
SMRT operates the North-South, East-West, Circle and Thomson-East Coast MRT lines and the Bukit Panjang LRT.
Measuring rail components manually was physically challenging, as engineers had to squat to check the dimensions of the rail and tracks every 50m, and of the third rail every 15m.
In contrast, the laser track trolleys can be pushed along the tracks easily and are equipped with sensors that continuously capture all three measurements at 0.5m intervals.
These trolleys were upgraded in early 2024 to include the ability to measure the position of the third rail.
SMRT also has an in-house track access management system that digitalises and simplifies processes for workers to get permission to go down to the tracks, saving around 30,000 man hours each year by cutting the time taken to complete paperwork.
The system is being used across 59 stations on the North-South and East-West lines, and 30 stations on the Circle Line, to optimise the use of short windows of engineering hours for maintenance works.