Southern Railway will run weekly summer special trains between Tirunelveli and Lokmanya Tilak Terminus to clear extra rush of passengers.   The Lokmanya Tilak Terminus Tirunelveli Special weekly train will leave Lokmanya Tilak Terminus at 12.50 hrs on Saturdays from April 30 to June 4 and arrive Tirunelveli at 02.15 hrs on Mondays, a railway release said here today.   Tirunelveli Lokmanya Tilak Terminus Special would leave Tirunelveli at 13.00 hrs on Mondays from  May 2 to June 6 and arrive Lokmanya Tilak Terminus at 23.45 hrs.