As of now there is no train service between India and Sri Lanka countries, because these countries don't have land connectivity to reach.
Now either option is by travel by train till nearest railway station:-
- Chennai Central/ Chennai Egmore
- Nagapattinam Junction
From Chennai, direct flight available to Sri Lanka (by air option)
2nd option is alight at Nagapattinam Junction Railway Station
Then take a ferry Nagapattinam-Kankensanthurai Ferry
From Kankensanthurai to Colombo Sri Lanka’s Capital City distance is 418 km, by train or bus you can reach there
Ferry fare will be around Rs 4000 per head.
From Delhi/Mumbai Direct flights available if you are not looking for ferry journey
In past There used to be a train from Madras to Dhanushkodi which is connected with a ferry to Talaimannar in Sri Lanka,
due to cyclones in 1964 near Rameswaram Dhanushkodi it vanished away and ferry service discontinued.
From thalaimannar to Colombo distance is 337 km.