section of the line was lowered into a cutting to eliminate numerous level crossings. Power signalling was provided between Richmond and Hawksburn at the same time, then on to Caulfield in 1921. Electrification of the line to Frankston occurred in three stages during 1922. In March 1922, the section from South Yarra to Glenhuntly station was electrified, with the section to Mordialloc being electrified in June 1922, and the final section to Frankston being completed by August 1922. The electrification of the line allowed for the introduction of Swing Door electric multiple unit trains for the first time. The introduction of power signalling on the line begun in 1933 with the section from Caulfield to Glenhuntly, with the remainder of the line converted in stages from 1958 to 1986. Triplication of the line from Caulfield to Moorabbin from two to three tracks was announced by Transport Minister Steve Crabb in 1984, at a cost of $10 million. Construction of the additional track was designed to increase peak hour capacity and to provide express services on the corridor, with time savings of more than 10 minutes from Frankston. Work begun in July that year with a completion by the end of 1985. The intorudction of services on the new track was delayed by two years till June 1987. Further plans announced in the 1970s included the extension of the third track to Mordialloc, however, these plans did not eventuate. The current bridge over the Patterson River was provided in 1974, replacing the previous trestle bridge. In 1981, Frankston line services commenced operations through the City Loop, after previously terminating at Flinders or Spencer Street stations. The commencement of operations involved the service stopping at three new stations—Parliament, Melbourne Central (formally Museum), and Flagstaff. The Loop follows La Trobe and Spring Streets along the northern and eastern edges of the Hoddle Grid. The Loop connects with Melbourne's two busiest stations, Flinders Street and Southern Cross, via the elevated Flinders Street Viaduct. From 2021, Frankston line services stopped operating through the loop as part of a timetable restructure. 21st century A 2007, restructure of train ticketing in Melbourne involved the removal of Zone 3, with Zone 3 stations being re-classified to Zone 2. This brought the cost of train fares down, improving system accessibility to the public. All stations between Patterson and Frankston were rezoned to Zone 2. At the 2010 state election,