SINGAPORE - Five major MRT service disruptions occurred in just the first quarter of this year, close to half the total number of incidents last year, The Straits Times has learnt.

According to figures on the Land Transport Authority (LTA) website, there were five service delays lasting more than 30 minutes between January and March 2015.

For the whole of 2014, there were 12 such disruptions, and in 2013 and 2012, just eight for each year.

The incidents this year included a four hour and 38 minute breakdown on the North-South Line on Feb 23, between Yew Tee and Kranji stations. This was due to a damaged power-collecting device on the train that affected the third rail, which supplies power to trains.

When the number of major services delays in the first quarter of this year are averaged out over 100,000km of train distance travelled, the incident rate is 0.07.

This is up from 0.04 in 2014, and 0.03 in 2012 and 2013. It is also higher than the 0.05 recorded in 2011, which saw two major breakdowns on the North-South Line in December that year.

But the overall number of service delays - which are defined as being more than five minutes - have reduced across the MRT network. The incident rate in the first quarter of this year was 0.79, down from 1.17 in 2014.

Four major service delays occurred in the LRT network in the first quarter, with all the incidents occurring on the Bukit Panjang LRT system. For the whole of 2014, just five such service delays took place across the LRT network.