TAIPEI - The main route of Alishan Forest Railway, a popular tourist attraction in Taiwan, will be closed for another three months due to safety concerns, the island's railway authority announced.

The 106-year-old railway which runs up to and through the mountain resort of Alishan in Chiayi County had four train derailments from Jan 18 to Feb 25, and the main route was immediately suspended after the fourth accident pending an investigation.

At a press conference held Monday, the authority announced that the main route between Chiayi station and Shizilu station will be suspended from service for another three months, but the branch lines will continue to operate.

The investigation team recommended the route remain closed until issues, including rotting sleepers and old trains, are resolved.

A batch of newly designed trains are being tested for potential dangers, said investigation team.

Apart from the derailments on Alishan Forest Railway, Taiwan's railway network has experienced 16 accidents so far this year.