18 December 1865 - Flinders Street to Princes Bridge 8 May 1888 - Collingwood to Inner Circle South Junction 8 October 1889 - Inner Circle North Junction to Reservoir 23 December 1889 - Reservoir to Mernda 21 October 1901 - Princes Bridge to Collingwood 5 December 1904 - Rushall to Merri
Electrified
31 July 1921 - Princes Bridge to Reservoir 16 December 1929 - Reservoir to Thomastown 30 November 1959 - Thomastown to Lalor 30 November 1964 - Lalor to Epping 27 November 2011 - Epping to South Morang 2 July 2018 - South Morang to Mernda
Closed
29 November 1959 - Lalor to Mernda
Reopened
29 November 1964 - Lalor to Epping 27 November 2011 - Epping to South Morang 2 July 2018 - South Morang to Mernda