A view of the construction of the Mylapore metro rail station on February 9.
| Photo Credit: M. SRINATH
Next week, Chennai Metro Rail would have connected Mylapore with Marina Beach through a tunnel for the upcoming phase II project. In about two years, trains will zip through these areas.
As Commissioner of Railway Safety (CRS) has given his approval recently, the tunnel boring machine (TBM) which travelled from Light House will make a breakthrough at Thirumayilai on February 9. The TBM’s drive comes to an end after a delay of a year and a half. The CRS approval was required for this TBM since the machine would drill nearly 10 metres away from the Thirumayilai MRTS station pile.
The machine was launched at Light House in September 2023, and was supposed to have finished the tunnel in a year.
According to Chennai Metro Rail Limited (CMRL) officials, the delay in constructing the tunnel shaft at Thirumayilai, the multiple changes of the cutter head discs (a component of the TBM), challenging soil conditions, temporary stoppage of tunnelling activity due to cracks in a school and a gas leak, have resulted in quite a lot of problems that obstructed the progress of tunnelling.
“It took a long time to build the tunnel shaft at Thirumayilai. The contractor in charge for building the Thirumayilai station delayed the shaft construction. It took time for the firm to relocate the vendors in the area and get access and then build the shaft. The contractor carrying out tunnelling too consumed a lot of time to replace the cutter head discs each time much longer than needed,” an official said.
“We also didn’t put too much pressure on the contractor carrying out tunnelling to complete it soon because the TBM will then come and wait outside the station. If this happens for an extended time, we will be paying a very steep amount as charges for the waiting period,” the official explained.
When there were cracks in a school building, and small amount of methane and carbon monoxide gases leaked from the site, the tunnelling was stopped for about a month’s time.
By September, the TBM reached close to the Thirumayilai station. “We had sent an application to the Railways for them to forward it to CRS. But they raised queries and that process too delayed the breakthrough. Finally, it was sent to the CRS, and he immediately gave the approval,” the official said.
Published – February 04, 2026 05:00 am IST
