The Eastern Union Railway had built a line from Colchester to Ipswich and they formed a new company, Ipswich and Bury Railway Company, chaired by John Chevallier Cobbold to build an extension from Ipswich to Bury St Edmunds which was known as the "Bury extension". It was granted parliamentary approval by Royal Assent on 21 July 1845 and the first train ran on ran on 26 November 1846. The Ipswich and Bury Railway Company was formally merged with the Eastern Union Railway Company on 9 July 1847.