A Singapore transit official says two maintenance staff working on elevated tracks have been hit and killed by an oncoming train.

Singapore's mass transit system has experienced a string of disruptions in recent years, denting the city-state's reputation for efficiency.

A spokesman for transit operator SMRT Corp., Patrick Nathan, said the two men had worked for the company for two months and were undergoing on-the-job training at the time of Tuesday's accident. He did not elaborate.

Singapore's Straits Times newspaper said five maintenance personnel were walking along one set of tracks, and the two victims crossed over to the other tracks, where they were hit by the oncoming train.

Such fatal accidents are unusual in Singapore.