JAPAN: East Japan Railway’s GMAC mobile maintenance unit is to ready be deployed from a base at Mito, following delivery of the third vehicle, the railway announced on April 16.

Branded GMAC for ‘next-generation maintenance machine’, the 1 067 mm gauge unit is derived from the ROMIS range of mobile track maintenance equipment developed by Robel. Working with its local partners Nippon Plasser and Mitsui Plant System Co, the company supplied two of the three elements, which were formally commissioned last year. The third vehicle was delivered in early 2021.


Robel has supplied the MMU Material Carrier and Mobile Work Vehicle. The former is designed to transport long objects such as rails and heavy materials including sleepers, and as well as the tools and equipment required for track repairs. Fitted with powered side doors for easy loading, it also has an elevating roof platform for overhead wire inspection.

The Mobile Work Vehicle is the heart of the unit, with an open floor area providing access for inspection and maintenance work to be undertaken on the track within the protection of the vehicle’s telescoping sides. Interior lighting and power supplies are incorporated, along with two 1·5 tonne cranes to transfer heavy items from the Material Carrier.


These cars have now been paired with the locally-manufactured Inspection Driving Vehicle. Powered by a 454 kW traction motor, this can run on its own at up to 45 km/h and haul the other two vehicles to and from worksites at 30 km/h. The vehicle is 15·6 m long and 2 944 mm wide, with a maximum height above rail top of 4 046 mm. It is fitted with 12 digital cameras on its ends and sides and a 3D laser scanner, able to take three-dimensional images of the infrastructure while on the move and upload them to a data cloud for further analysis.

JR East confirmed that the GMAC/MMU would initially be based at Mito, where it is to be deployed on the section of the Joban Line between Tomioka and Haranomachi during the second half of 2021. Further testing is also to take place, with a view to the concept being used on other parts of the 1 067 mm gauge network.