Mobile connection problems in train stations and along train tracks will soon be over as SingTel said it has completed 3G and 4G network upgrades along the North-East Line that stretches from HabourFront to Punggol.

The telco also improved its mobile networks along parts of the Circle Line that runs from Pasir Panjang and Botanic Gardens and Nicoll Highway. Twelve out of the 29 Circle Line stations - from Harbourfront to Caldecott - now have stronger 3G connections for more users and the faster 4G networks, SingTel said on Friday.

This is part of a new undisclosed investment SingTel is making to boost connections islandwide - including some 90 buildings like malls, hospitals and hotels by the middle of next year (2014) - to meet consumers' growing demand for mobile data. The investment is in addition to the telco's $150 million 3G and 4G upgrade efforts completed in April (2013).

Mobile upgrades along the North South Line and East West Line are still ongoing. SingTel said it is still working with SMRT to obtain more maintenance sessions to expedite the upgrades and will provide updates in due course. "To avoid disruption to MRT services, work can only be performed during hours when trains are not in operation," the telco said in a statement.