companies also transport petroleum products from refineries to storage terminals using the zone. Cement plants also use the railway system extensively. Food grains are also transported through freight trains. Most of the lines inside ports, thermal stations, manufacturing industries and owned by the respective companies and the zone provides a link connecting its network and the wagons and locomotives. There is a wagon care centre in Tondiarpet, Chennai. The zone has electric loco sheds at Royapuram, Erode and Arakkonam. Diesel loco sheds are present at Tondiarpet, Golden Rock, Ernakulam and Erode. Most of the important routes are electrified and only low traffic lines are unelectrified. However, it is common to see diesel locos in electrified lines due to various operational constraints. It is also common to see other zones' locomotives operating inside the zone and vice versa. Since the zone has little freight traffic compared to other zones and huge passenger traffic (which are run at low fares across the country), the zones' finances are often in a bad shape. Mangalore, Salem, Katpadi and Chennai acts as the first category entry/exit points of southern railway zone from other nearby railway zones due to this all trains make a technical halt at these stations to make a crew change. Jolarpettai and Arakonam acts as the second category entry/exit points of the zone. Junction railway stations in this zone are listed below. Erode Junction Salem Junction Karur Junction Omalur Junction Jolarpettai Junction Katpadi Junction Walajah Road Junction Villuppuram Junction Arakkonam Junction Chengalpattu Junction Vriddhachchalam Junction Tiruchchirappalli Junction Cuddalore Port Junction Mayladuthurai Junction Thanjavur Junction Tiruvarur Junction Nagapattinam Junction Nidamangalam Junction Nagercoil Junction Tirunelveli Junction Tenkasi Junction Maniyachchi Junction Virudhunagar Junction Madurai Junction Manamadurai Junction Karaikkudi Junction Dindigul Junction Pollachchi Junction Podanur Junction Coimbatore Junction Coimbatore North Junction Irugur Junction Mangalore Junction Shoranur Junction Palakkad Junction Thirssur Punkunnam Junction Ernakulam Junction Kayankulam Junction Kollam Junction Peralam Junction Tiruturaipundi Junction Villivakkam Junction Basin Bridge Junction Pattabiram Junction Terminal railway stations in this zone are listed below. Chennai Central Railway Station Chennai Beach Ranippet Chennai Central Suburban Terminal Chennai Egmore Mettupalayam Mangalore central Thiruvananthapuram Central Thiruvananthapuram Kochuveli Nilambur Road Guruvayur Cochin Harbour Terminus Kanniyakumari Tiruchendur Thoothukudi Rameshwaram Bodi Nayakkanur Mannargudi Velankanni Point Calimere Tranquebar Puducherry Mettur Udhagamandalam (Ooty) Pattabiramam East depot Anna Nagar West Infrastructure Assets Southern Railway has many factories and sheds: Mechanical Workshops Carriage, Wagon and Loco Works, Perambur, Chennai Central Workshop, Ponmalai,