train from Trivandrum to Chennai

We are a family of 3 (parents and 14 year old daughter) spending February and March in India. The plan is to fly in to Kochi and head down the coast to Trivandrum. Does anyone know about an overnight train from Trivandrum to Chennai? Times? cost? I thought I would book those tickets in advance and have them sent to whatever hotel we book in Kochi.
We'll have 2 weeks in Kerala before heading to Chennai in time to catch an 8 day Tamil Nadu pilgrimage tour, then fly north.

2 weeks kerala/ 8 days Tamil Nadu/ fly to Rajasthan (Jaipur, pushkar, if enough time go further west), train to Agra and environs, train to the Corbett Tiger reserve, on to Rishikesh and home from Delhi. Too much? We want lots of hang out time, just watching India from a bench, a cafe, a market.

Trivandrum to Chennai

Train 2624 departs Trivandrum daily at 14:30 and gets to Chennai Central at 07:00. (this train goes via Cochin)

First Class air con = Rs 2649
2-tier air con = Rs 1403
3- tier air con = Rs 907
Sleeper Class = Rs 342 (not air con)


Train 6124 departs Trivandrum daily at 16:20 and gets to Chennai Egmore at 08:40. (this train goes via Madurai)

2-tier air con = Rs 1270
3- tier air con = Rs 813
Sleeper Class = Rs 299


The following info is for others.


Chennai to Trivandrum

Train 2623 departs Chennai Central daily at 20:00 and gets to trivandrum at 11:55 (this train goes via Cochin)

First Class air con = Rs 2649
2-tier air con = Rs 1403
3- tier air con = Rs 907
Sleeper Class = Rs 342 (not air con)


Train 6123 departs Chennai Egmore daily at 19:30 and gets to trivandrum at 11:45 (this train goes via Madurai)

2-tier air con = Rs 1270
3- tier air con = Rs 813
Sleeper Class = Rs 299