EDI/Bombardier Interurban Multiple Unit 120 series (IMU120)

In 2001, IMU121-124 were introduced into service to cope with the extra services needed for the new Airport line, which opened that year. There are only four of them, each a 3-car set, making just 12 cars in all. Like the IMU100s they were built by Walkers at Maryborough, this time in partnership with Adtranz, and two sets can be coupled to make a 6-car train.

The IMU120s are fitted with electric plug doors as opposed to air operated plug doors on the IMU100s, they are fitted with one A/C pod per car as opposed to two and the cooling system has been changed to water cooling which eliminates the noise associated with the traction blower fans. The layout's different too: where the IMU100s have their motors in the end and middle cars with a driving trailer at one end, the IMU120s have motor cars at both ends and a trailer in the middle.

Like the rest of the IMU fleet, they're expected to be around for a while yet. In a 2021 answer to a question in Parliament, the Transport Minister put the IMU120s down for retirement from 2038, the same year as the IMU100s.