GUANGZHOU: Tunnelling works for the Mass Rail Transit Sungai Buloh - Serdang - Putrajaya (SSP) line are scheduled to start in the first quarter of next year and digging work is expected to be completed in mid-2019. Mass Rapid Transit Corp Sdn Bhd (MRT Corp) strategic communications and stakeholder relations director Datuk Najmuddin Abdullah revealed that the 13.5-kilometre tunnelling works for the SSP line would start in Jalan Ipoh and end at Bandar Malaysia (South) in Kuala Lumpur. "A total of 12 tunnel boring machines (TBM) are to be used in the works - 10 variable density (VD) TBMs and two Earth Pressure Balance (EPB) TBMs – the additional machines are required as the underground alignment is longer than the Sungai Buloh - Kajang (SBK) line," Najmuddin told reporters during a recent factory acceptance test (FAT) for two of the four newly purchased TBM at the Guangzhou Herrenknecht Tunnelling Machinery Co Ltd factory in China. Najmuddin explained that the FAT is a validation process that takes place to demonstrate that the system and manufacturing designs meet the specifications set in the contract. On the TBMs, Najmuddin revealed that four are newly purchased from Herrenknecht China with each costing between RM40 million and RM60 million while the eight other machines were refurbished from the SBK line. Among others who were present for the FAT included MRT Corp SSP line underground works director Blaise Mark Pearce, MMC - Gamuda KVMRT (T) Sdn Bhd (MGKT) tunnelling director Gusztav Klados and MGKT tunnelling general manager Ng Hau Wei. Asked on the biggest challenges when it comes to tunnelling works in KL, Ng said it would be the tricky karstic limestone geology, unpredictable cavities, fissures and fractured rocks in a densely built-up city. Najmuddian said the MRT SSP project was 12.05% completed, and is expected to reach 19% by the end of the year. Najmuddin added that the first phase of the SSP line is schedule to be completed by July 2021 while the full completion of its 52.2km alignment covering 37 stations (11 underground) is scheduled for full completion the following year.