I use to book my tickets 4 months in advance. Last week when I tried to book ticket to Thiruvarur from Chennai in Karaikal Express (16175), I got a message in the screen as "sorry no matches train found", tried to enquire it in helpline, no one has given prompt reply. Today while surfing IRCTC again I found that no trains available after 11th October 2012 from Chennai to Thiruvarur. What happened to this train 16175 and 16176. Pls respond.