The Eastern Counties Railway Company was incorporated in 1836 to build a line from Shoreditch to Yarmouth via Colchester, Ipswich and Norwich. The first public trains did not run until 20 June 1839 and then only between Mile End and Romford. The Shoreditch to Brentwood section opened in1840, and Colchester was finally reached in 1843.

Reference: http://www.esscrp.org.uk/gainsborough/history/history.php