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 run till Villupuram Junction.

• This section has 2 dedicated lines for suburban train operations apart from 2 main line for mixed traffic.
• EMUs are operated along 3rd and 4th main lines during peak hours.
• 5th and 6th rail lines are planned.
• 9-car and 12-car EMU are operated in this sector.

• This section also has 2 dedicated lines for suburban train operations apart from 2 main line for mixed traffic.

• 9-car, 12-car EMU & MEMU are operated in this sector.

• 8-car MEMU are operated in this sector.

• MEMU service operate between Chennai Beach and Vellore Cantonment via Katpadi.

• 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