In a dimly lit tunnel about 100m from Bugis MRT station, a rail-cutting machine roars to life in the dead of night.
Sparks fly as the blade works its way through thick steel, in a scene that plays out every night along the North-South and East-West MRT lines (NSEWL).
While the rest of Singapore sleeps, rail operator SMRT deploys an average of 50 workers each night to replace worn or defective sections of the running rails, which MRT trains travel on.
About 100m of rail is changed out each night to ensure smooth and safe rides for commuters.
It is a race against time as there is only a three-hour window between 1.30am and 4.30am during which this track renewal work can be done.
In the wee hours of the morning on Aug 12, 2023, The Straits Times was invited to see the process.
Mr Lam Sheau Kai, president of SMRT Trains, said rail replacement has become a constant feature in the maintenance of the NSEWL, two of Singapore’s oldest and most heavily used rail lines.
The lines are more than 30 years old and 102km long in total. A train track is made up of two rails and with a track running in each direction, this means there are about 200km of tracks and 400km of rail on the NSEWL that need to be maintained.
Track renewal is conducted at up to five sites along the NSEWL every night, compared with three sites 10 years ago.
The 35km Circle Line, which started operating in phases from 2009, will likely require a similarly high tempo of rail replacement in about five years’ time as well, and SMRT has already started to plan for this.
Saturday’s rail change operation was a relatively straightforward one, involving the replacement of about 18m of rail near Bugis station, and could be completed in one go.
There are more complicated works involving the replacement of switch rails, which move mechanically to divert trains from one line to another, and crossings, where rail lines intersect with one another. Such works can take three consecutive nights.
WEAR AND TEAR
Replacement works are usually needed when a section of rail is worn down to a certain threshold.
Stretches near stations where trains brake tend to have more wear, and bends create uneven wear and tear on the rail.
On a daily basis, SMRT engineers are required to plan for replacement works on the NSEWL.
On Saturday, there were also rail replacement teams working in Yio Chu Kang and Buona Vista, for instance.
Real-time data is used, and plans will change if a severe defect is detected elsewhere.
In Bugis, workers were given a safety briefing before they headed to the station platform. The electric current to the tracks was also cut off so that it was safe for them to go into the tunnel.
A diesel-powered locomotive carrying equipment and a crane used to lift and lower rail segments was driven to the worksite from Changi Depot. An 18m rail segment weighs about a tonne.
Work began in earnest once the locomotive was in place.
By then, it was nearly 2am.
The workers cut out the worn section of rail.
A new piece of rail was then lowered in its place.
This new piece had to be aligned so that there was a precise 25mm gap between it and the rest of the existing running rail.
This was to prepare for welding, which Mr Lam said was a key step.
This was because the joint holding the pieces of rail together is the weakest point, and can pose a risk if the welding is not done properly.
One initiative SMRT has embarked on is the testing of a welding mould that has a built-in material that expands on heat, creating the tight seal that is required.
Currently, workers need to apply a paste to achieve a similar effect, a process that is time-consuming and lacks consistency.
Mr Lam said: “These are the challenges when you only have three hours a night, and you really have to make effective use of it.
“We try to find methods that are more consistent in quality and also take a shorter time, because sometimes, the quality of work suffers when you are rushing.”
With the heavy machinery being used, and the extreme heat generated by the welding equipment, which can go up to 2,000 deg C, Mr Lam said safety is paramount.
HOT HOT HOT
“Underground, we work in tight spaces, and it gets hot, so we turn on the tunnel ventilation fans so that the heat gets dissipated, and the guys get good air,” he said.
“This does create some noise, and we hope Singaporeans and residents who are near these areas understand the need for this.”
SMRT senior engineer Shazni Jaffar was among the 15 men working in the cramped and hot tunnel in Bugis.
The 32-year-old, who has been in the industry for close to four years, hopes more people will appreciate the work that he and his colleagues do.
He said: “Without the tracks, the trains cannot run.”