The ongoing downpour across sub-Himalayan Bengal and Sikkim triggered a landslide in one of the sites of the Sevoke-Rangpo railway route in Sikkim on Tuesday.
The ambitious railway project has been planned to include Sikkim on the Indian railway map.
The 45km-long railway route that would connect Rangpo, the bordering town in Sikkim, would have 14 tunnels.
On Tuesday morning, the external wall of the adit portal of tunnel 7, which would connect Geilkhola and Rabijhora, collapsed as the landslide occurred near Rabijhora.
An adit portal is a horizontal or semi-horizontal passage made in the side of a hill or mountain for mining and construction. Adits also have some other functions, like access to a mine, facilitating ventilation or draining water.
Sources at Ircon International Limited, a government of India undertaking implementing the railway project, said the incident of slope failure occurred due to a landslide triggered by heavy rainfall.
“According to reports, there had been no casualty or injury to any worker or person and also no loss of any machinery or railway asset,” said a source.
The landslide occurred about 30 metres away from the tunnel, and the main tunnel and the adit tunnels are safe, the source added.
Ahead of the incident, precautionary measures were taken to remove the men and machinery from the site.
Later in the day, the authorities took up the work to remove the debris and protect the site.
Weather experts said the monsoonal trough was causing incursion of moisture from the Bay of Bengal, which could lead to moderate and isolated rainfall in sub-Himalayan Bengal and Sikkim during the next few days.
“Such rainfall can lead to flash floods, waterlogging, mudslides, landslides and a reduction in visibility in the hills. People should be on alert,” said an expert.