http://www.channelnewsasia.com/news/singapore/2-smrt-staff-dead-in/2625352.html?cid=cna_editorspick_070814
"(They) were part of a technical team that went down to the track to investigate a reported alarm from a condition monitoring device for signalling equipment. Permission to access the track was authorised," said Mr Nathan.
"Initial findings indicate that before the accident happened, the team was moving in a single file on the walkway beside the track, on the way to the location of the signalling equipment."
The brother of a signals officer who witnessed the accident told Channel NewsAsia that the signals officer was "traumatised".