excursion trains operated to take passengers to picnics, race meetings or other social functions. As the South Island rail network was gradually extended and eventually completed, various long-distance passenger services were introduced and replaced. Early long-distance services included the Culverden Express; the South Express, a Christchurch – Invercargill service inaugurated following the completion of the Main South Line; and the West Coast Express, which connected to the West Coast of the South Island. Some of these services were later replaced with railcars as steam was phased out; others with new services which, it was hoped, would revitalise the flagging fortunes of those routes. Such was the case with the South Express, which were replaced with the prestigious South Island Limited in 1949, and the Southerner in 1970. The Picton Express was introduced in 1945 upon completion of the Main North Line and, following a period during which railcars ran on this route, was superseded by the Coastal Pacific. Following a replacement railcar service, the West Coast Expresses was superseded by the TranzAlpine. The Coastal Pacific and the TranzAlpine are the only passenger trains to depart from Christchurch. Following the success of the electrification of the Midland Line between Arthur's Pass and Otira, it was decided in 1925 to introduce electrification to Lyttelton. On 14 February 1929, the electrified line was opened using a 1.5 kV DC system, with an electrical substation at Woolston. This was originally intended to be the first stage of a larger plan for Christchurch passenger services. Six EC class electric locomotives operated passenger services between Christchurch and Lyttelton, until reaching the end of their working lives in 1970, with the last electric train service running on 19 September 1970. With the withdrawal from service of the EC locomotives, the electrification was removed as the cost of purchasing replacement locomotives and maintaining the electric infrastructure could not be justified. The Electric Traction Group based at the Ferrymead Historic Park has preserved and returned to operational status locomotive EC 7. Suburban passenger services in Christchurch were eventually cancelled due to lack of patronage. By 1951, the mixed trains to Little River and Southbridge had disappeared, with the Ashburton passenger service following in 1958 and the last run of a mixed train to Springfield in June 1968. With the opening of the Lyttelton road tunnel in 1964, patronage of passenger trains to Lyttelton slowly declined to the point where