He saw his best friend crushed by an oncoming train, in a fatal accident that happened just months after they joined SMRT as trainees.
But the thought of quitting the company or taking on roles un- related to track work has never been an option for Mr Muhammad Hatin Kamil, 25, though SMRT had asked if he would like to change departments.
Instead, he completed his training and is now working as a technical officer in the signal department, where he sometimes does track- related work.
Mr Hatin said he worked hard on overcoming his fears - by facing them. "It takes time to recover, quite a long time," he said. "I knew if I were to change jobs, things would remain the same; the scar would still be there.
"People say tough times don't last, tough men do - that is what a friend taught me."
On March 22 last year, Mr Hatin was part of a 15-strong team sent to investigate a possible fault near Pasir Ris MRT station at around 11am. As they were getting onto the track, a train hurtled towards them at 60kmh - unbeknown to the group.
It narrowly missed Mr Hatin but killed two other trainees: Mr Nasrulhudin Najumudin, 26, and Mr Muhammad Asyraf Ahmad Buhari, 24.
When he turned to check on Mr Nasrulhudin, who was his "best buddy", he saw the pair hit by the train. One was crushed and the other flew some 5m away.
It was not easy, though, said Mr Hatin, recounting how he found himself unable to travel by train in the weeks after the accident.
"I had flashbacks each time I took one. I would think, 'So this is the speed that it hit my friends'," he said, adding that he stopped work for four months, and saw a psychiatrist.
He also used to recall his conversation with Mr Nasrulhudin on the morning of the incident.
"While I was in a train with Nasrul at the Tampines MRT station, he pointed to show me where his home was," said Mr Hatin. "The next day, I was there - to see his body."
It took him about six months after the accident to return to work on tracks, although some colleagues advised him otherwise.
But even now, whenever he is on the tracks, his gaze would flit around involuntarily, looking around to see if there was any train heading his way, said Mr Hatin.
"The anxiety is there. I am scared it might happen again," he said, adding that safety and communication are paramount to him.
Still, looking back at what happened, he said he believes everything happens for a reason.
"Sometimes, people make mistakes. Leave it and let go - you have to move on," he added.