and repainting and strengthening the seat modules, removal of the luggage racks and advertising boards, overhaul of windows and doors including the motors that were worked by air and a general clean of the exterior and new green and gold stripes applied. The refurbishment of over half of the Hitachi M cars also included improved air-conditioning in the driver's cab and double-thickness windscreens, with aluminium replacing the original rubber surrounds. These M car works were completed by early 1994. After these upgrades were made, the non-upgraded M cars were no longer allowed to lead a train in revenue service, effectively making them B units. Two M cars have been preserved in their original unmodified form, while a third M car (187M) as modified by the PTC is on static display at the AHRS Museum in Williamstown. In late 2007, Hitachi set 37M-1979T-36M-110M-1910T-42M was modified to meet driver union requirements (including cab air conditioning) and also re-stickered into Connex livery. All remaining sets have since received the same treatment, as well as a refurbished interior. In 2008, the remaining seven 6-car trains were again modified, mainly with a more powerful driver's air-conditioning system replacing the small vents on the roof, however three other 'leading' cars (9M, 89M and 225M, now 277M, 281M and 296M respectively) were not modified and relegated to being in the centre of the trains indefinitely. Retirement New X'Trapolis and Siemens trains were progressively introduced from 2002 to replace the aging Hitachi fleet. The X'Trapolis and Siemens trains have features such as push button operated doors and air conditioning, the lack of the latter feature making the Hitachis unpopular with Melbourne commuters. A majority of the sets were withdrawn between 2002 and 2005, with withdrawn carriages having been either scrapped, sold to private buyers across Australia, stored, or acquired by railway museums and preservation groups. Three Hitachi motor carriages were lifted and fixed to the roof of Easey's Restaurant in Collingwood. The final six 6-carriage trains were to be withdrawn after the 2006 Commonwealth Games, but instead received a minor refurbishment and remained in revenue service until December 2013, due to a high increase in patronage. A report in February 2007, by which time 31 trains in the Siemens fleet were out of service due to safety concerns, said the Victorian Government was negotiating to lease one 6-carriage set from rail preservation group Elecrail, and repurchase another 3