91 three-car Comeng sets, as well as the single prototype 4-car 4D. To replace the Hitachis, 58 three-car X'Trapolis were ordered with the first entering service in December 2002. The Comengs were refurbished between 2000 and 2003 by Alstom at Ballarat North Workshops. When Connex Melbourne took over the M>Train franchise in April 2004, it took over all of its rolling stock including the remaining Hitachi and Comeng sets as well as the Siemens Nexas fleet. A class locomotives and MTH carriages were hired from V/Line for services on the unelectrified Stony Point line. These were replaced in April 2008 by Sprinters. Because the modifications made by both operators had made the Comeng fleets incompatible with each other, Innovonics Limited modified the sets from both operators to enable them on the entire system again, along with a CCTV upgrade. The majority of rolling stock was owned by the Victorian Government business enterprise VicTrack. Maintenance of the Hitachi and Comeng sets was outsourced to United Group, while Siemens maintained the Siemens Nexas fleet. In October 2004, Alstom were contracted maintain the Hitachi, Comeng and X'Trapolis fleets. The maintenance contract was included in the sale of Alstom's Australian operations to United Group. Connex was also responsible for the maintenance of the electrified metro network, which was contracted out to Mainco, a subsidiary of the United Group. The Department of Transport also had input into infrastructure related issues and major rail projects. 2009 heatwave issues During January 2009, Melbourne experienced several days of extreme heat with temperatures in excess of 43 °C – the hottest heatwave since records were kept from the mid-1880s – with a maximum temperature reached of in the Melbourne central business district. Prior to this, the ambient temperature was between . Connex was unable to guarantee services across the network. This was highly controversial as, in previous years, 'heatwaves' did not cause train cancellations. The heat-distortion of tracks has been attributed to the lack of expansion joints within newly replaced rail. Figures based on Connex media releases for the same period show the numbers of cancelled services exceeded one third of total services. On 29 January 2009, over 500 services were cancelled. Next day services on eight lines were cancelled and the City Loop closed in the afternoon owing to the extreme weather (at the height of the heatwave) and knock-on effects, and the loss of power at the