Two labourers were killed when an under-construction tunnel of Sevoke-Rangpo (Sikkim) railway line caved in near Kalimpong on Thursday night.

The incident occurred around 10.30pm at Bhalukhola, about 25km from Kalimpong.

Police said seven labourers had been brought out of the debris but two of them died at Kalimpong district hospital.

“All workers are said to be from Bihar,” said Kalimpong superintendent of police Hari Krishna Pai.

Almost 86 per cent of the 44.98km rail link will run through 14 tunnels.

Each tunnel will have a diameter of right meters.

The total cost of the project, which started in 2018, is pegged at around Rs 4,000 crore.