of Port Phillip, and runs alongside the Nepean Highway for much of its length. At Frankston station, electrified services terminate with Metro Trains operated diesel services continuing to Stony Point. Most of the rail line goes through built-up suburbs and some industrial areas, with small sections of the line passing through more open countryside, passing by open fields and farms. Stations The line serves 28 stations across of track. The stations are a mix of elevated, lowered, underground, and ground level designs. Underground stations are present only in the City Loop, with the majority of elevated and lowered stations being constructed as part of level crossing removals. From 2023, Glenhuntly station will be lowered as part of level crossing removal works. In 2025, Parkdale station will be elevated, with Highett, Mordialloc, and Seaford stations being elevated from 2029 for similar works. Aspendale station will also be lowered from 2029. Infrastructure Rolling stock The Frankston line uses three different types of electric multiple unit (EMU) trains that are operated in a split six-car configuration, with three doors per side on each carriage. The primary rolling stock featured on the line is the Comeng EMUs, built by Commonwealth Engineering between 1981 and 1988. These train sets are the oldest on the Melbourne rail network and subsequently will be replaced by the mid 2030s. Siemens Nexas EMUs are also widely featured on the line, originally built between 2002 and 2005 these train sets feature more modern technology than the Comeng trains. The final type of rolling stock featured on the line is the X'Trapolis 100 built by Alstom between 2002 and 2004, and 2009 and 2020. All of these rolling stock models are widely used on other lines across the metropolitan network and work as the backbone of the network. Alongside the passenger trains, Frankston line tracks and equipment are maintained by a fleet of engineering trains. The four types of engineering trains are: the shunting train; designed for moving trains along non-electrified corridors and for transporting other maintenance locomotives, for track evaluation; designed for evaluating track and its condition, the overhead inspection train; designed for overhead wiring inspection, and the infrastructure evaluation carriage designed for general infrastructure evaluation. Most of these trains are repurposed locomotives previously used by V/Line, Metro Trains, and the Southern Shorthaul Railroad. Planned rolling stock From the middle of 2020s, the next generation of the X'Trapolis family of