Madras to Jolarpettai was completed by 1862 only. (Jolarpettai is JTJ, which is on the MAS-CBE route).
Like I said, initially there was a mail train on Madras-Jolarpettai-Calicut route, which had slip coaches to Bangalore. This is the present day 12601/02 MAS-MAQ mail. The slip coaches were detached at JTJ and proceeded to BNC. In 1908, this slip coach service was de-linked and started running as a separate train, which is the present day MAS-SBC mail.
Delhi was not an important place then....
more... Delhi only became important in 1911 after it became the capital. Till then only Madras, Calcutta and Bombay were the important cities in the country.
More Indians used the trains than Britishers. The British constructed many of the lines for famine relief (to move food and supplies faster during famines). The entire MAS-GTL-RC line and many branch lines in Rayalaseema area were constructed for famine relief.