The term "Unofficial name" for this particular train looks incorrect for me. It was an official name (not now) and trains were running for several years with that name. It was running upto Dhanushkodi and Indian Railways were operating a Bot service upto Talaimannar in Srilanka to connect India and Srilanka (Srilanka was part of India and it was an area ruled under Madras during that time, upto my knowledge but not having source evidence right now). But, I have attached the south Indian railway map of year 1931 which clearly shows the Boat service. One more additional information also, I have read that, the rail link between Rameswaram and Dhanushkodi was washed away by some natural disaster.
