The challenge of the Shatin to Central Link (SCL) project is multiplied by the complex arrangement under which the West Rail Line (WRL) and the Ma On Shan Line (MOL) will be transformed into the future Tune Man Line (TML) connecting the east and west parts of the New Territories by rail in 2019, all with 8-car trains. This will entail converting 7-car trains running on the WRL to 8-car trains and replacing 4-car trains running on the MOL with 8-car trains. A mixed fleet of 7-car/8-car trains and 4-car/8-car trains has been running on WRL and MOL from January 2016 and January 2017 respectively during this transition period, with gradual increase of 8-car trains. Railways Branch of EMSD had conducted strict verification on the concerned trains and mixed fleet operations to ensure the all railway safety perspective satisfied for safe operation for passenger service. Finally, all trains in MOL and WRL have changed to 8-car trains in Dec 2017 and May 2018 respectively.