The South West Frontier line of Chennai Suburban Railway is the longest line running South-west from Chennai (Madras) City covering a distance of almost 289 km. Suburban services terminate at Arakkonam and MEMU services currently run till Vellore Cantonment which will be extended up to Villupuram upon completion of Vellore Cantonment and Villupuram section.
This section has been gauge converted and is being electrified along with passenger services are operating since June. Currently five passenger trains ply over this section