Building tunnel below railway tracks: when train services were operated slower for Chennai Metro’s tunnelling work

For nearly six days in March if you boarded one of the express trains but wondered why it slowed down at Perambur, it was because Chennai Metro Rail was busy boring the earth to create a tunnel for the upcoming 116-km Phase II project. While Chennai Metro Rail carried out tunnelling under the four railway tracks in Perambur station, authorities decided to operate trains slower than usual as an additional safety measure.

The work was executed to build an underground network in this location. In about three-four years, residents of Perambur will not only have access to railway station but also a Chennai Metro Rail station close by. A massive tunnel boring machine (TBM), Kalvarayan, which started its journey at Ayanavaram in April last year, drilled the earth for 857 metres to build a tunnel till Perambur, including the stretch under the Perambur railway tracks.

The underground stretch between Ayanavaram to Perambur is a part of Corridor 3 of the Phase II project (between Madhavaram to SIPCOT via Ayanavaram and Perambur). Light House to Poonamallee (Corridor 4) and Madhavaram to Sholinganallur (Corridor 5), the other two corridors of the Phase II project are under construction as well.

According to officials of Chennai Metro Rail Limited (CMRL), they took numerous precautionary measures during the time when the TBM was crossing the railway track. “To ensure there were no settlements, cracks or any other issue affecting the station or the track, we had installed equipment like ground settlement and building settlement markers. We checked the reading every hour and shared them periodically with the railway officials. Also, railway officials informed us that the speed of goods or express passenger trains that pass through Perambur will be reduced to 20 kmph for a small stretch as well as an additional safety measure,” an official said.

From 21 March to 26 March, nearly 25 trains that went past Perambur operated at 20 kmph between Vysarpadi and Perambur, an official of Southern Railways said.

While one TBM has reached Perambur, another one will cross the tracks and reach the location in another four months.