The IMUs were introduced especially for the Gold Coast Railway in 1996, but are not necessarily restricted to this line as they also operate some Nambour services and now the Airport services.

As with the EMUs and SMUs, these units are fully air conditioned with window tinting and woollen carpets. The IMUs are fitted with a mobility impaired access toilet, upgraded seating, luggage racks and storage spaces. Hearing impaired commuters are able to make use of the hearing aid loop to hear public address announcements. The IMUs are also fitted with full video surveillance and emergency communication systems.

Train drivers have access to full computerised information about the performance of the train, while other computers go about their task of controlling the GTO (gate turn-off) thyristor three phase traction converter and three phase electric traction motors.

The trains were produced by Walkers Ltd. Maryborough in association with Adtranz of Switzerland who provided the traction, auxiliary and computer control systems.

In 2001, the IMUs were upgraded with features for disabled commuters including painting the commuter doors yellow for the visually impaired and installation of longitudinal seating for easier wheelchair access.