They had been "best buddies".
But the friendship between two SMRT maintenance staff came to a tragic end on Tuesday when Mr Muhammad Hatin Kamil saw Mr Nasrulhudin Najumudin killed by a train as they went to inspect the track near Pasir Ris MRT station.
It was the first time 24-year-old Mr Hatin and 26-year-old Mr Nasrulhudin were on the tracks during the day. The trainees joined the train operator only in January.
They were part of a 15-strong team sent to investigate a possible fault after high voltage was detected from a point machine there, said Mr Hatin.
They walked in single file, with Mr Nasrulhudin and Mr Muhammad Asyraf Ahmad Buhari, 24, second and third in line respectively behind a supervisor. Mr Hatin was the fifth person.
To reach the point machine, Mr Hatin told The Straits Times, the group had to cross the third rail supplying power to trains - which was still live - to get on the track.
"We didn't realise that there was a train coming towards us from this second track, going to our track, the first track," he said. "After I put my foot over the rail my senior technical officer behind shouted: 'Train is coming! Train is coming!'"
Mr Hatin saw the train nearing and his friend running towards the sidewalk. Mr Hatin quickly put his foot back on the walkway and hugged the railing.
When he took a second to check on Mr Nasrulhudin, he saw the trainee crushed by the train. But Mr Nasrulhudin was not the only casualty. Mr Hatin said: "Aysraf's body flew over behind me, like 5m away."
The supervisor walking in front of them avoided the train by jumping onto the walkway and squatting.
"This happened right in front of my eyes," said Mr Hatin. "I couldn't think. I went back to the platform, I couldn't do anything."
No one knew a train was coming, he recalled. "Our environment up there is different - you wouldn't be able to hear the train coming," he explained, adding that their supervisor had not said anything in the moments before the accident.
"The person in charge knows the system because they are more senior than us. Our job was to observe.
"It's very harsh. I don't know who is at fault."
SMRT revealed yesterday that the 15 men were split into two groups - six in front near the point machine and nine at a distance behind. It is unclear how exactly the supervisor in front managed to escape and why the two deceased did not.
Mr Hatin and Mr Nasrulhudin had known each other since their first days on the job as SMRT maintenance staff in January.
"He was my best buddy. He was my everything... my work buddy," said Mr Hatin.
"He was always with me; we ate breakfast at 4am together."
The pair had been on the tracks at night previously, and also worked together on shifts. But Mr Asyraf and the fourth trainee in the group had never been on the tracks before and Tuesday was their first time.
Mr Hatin and other SMRT staff arrived at Mr Nasrulhudin's home in Tampines Street 12 yesterday morning to pay their respects.
When he saw his friend's body, Mr Hatin broke down.