Rail claws are used to secure the third rail whereas they kept a rail to the trains.
Technically, the incidents on December 15 and December 17 are mainly due to the damaged third rail power which caused the third rail to spoil in the North South Line, south of Bishan MRT Station. At the point of checks on December 18, 21 rail claws were dislodged.
SMRT had decided to have positive-locking claws which will start in April 2012 and this might end in January 2013. This will replace all claws to prevent the incidents from happening again.
- ↑ http://www.straitstimes.com/The-Big-Story/The-Big-Story-3/Story/STIStory_789644.html MRT breakdown COI: Weakness of 3rd rail claws not new