Metro is tackling track improvements head on, with a 10-day rail grinding program now underway, and ballast (the rock that supports train tracks) replacement works completed during the weekend.Metro has secured the use of a switch grinder from Sydney's CityRail - a brand new machine that has been used to grind up to 9.5km of track this week, to improve track adhesion, reduce wear, and make for a more comfortable ride.Metro also recently trucked in 1,600 tonnes of rock, or ballast, which will be placed under track to give greater support and flexibility to rails and to also be used during track slewing (track straightening) works.The rail grinding, track straightening and ballast replacement form part of Metro's $145 million first year maintenance plan to improve the punctuality and reliability of train services.The eight-stone rail grinder, a custom-built truck that also has special rail wheels fitted to allow it to travel on train lines, was leased from Sydney's CityRail for 10 days, with Metro hoping to lease a 24-stone grinder - that can grind three times as fast - for a much larger works program scheduled from June.Grinding improves the profile of the rail, which increases the interface between the train wheels and the track, providing greater contact and friction for braking.The brand new road/rail vehicle is the fourth of its kind to be manufactured in Australia and won the 2009 Ken Eriksson Achievement Award for its grinding capabilities.The switch grinder has already been put to use at Malvern, Springvale, Noble Park, Ormond, Mordialloc, Hallam, Highett and Narre Warren.