NOW ON test on a refurbished IC3 DMU in Denmark is an innovative mechanical transmission developed by ZF Bahntechnik GmbH. The AS Rail auto-shift transmission is developed from an automotive version used in the lorry market for around five years. AS Rail is also being fitted to Danish State Railways’ AnsaldoBreda-built IC4 DMUs, the first of which is expected to be delivered in September, and ZF is expecting an order from main contractor Bombardier to supply transmissions for refurbishment of the entire IC3 fleet.

Unlike the hydrodynamic transmission common in modern DMU applications, AS Rail uses a mechanical gearbox with conventional clutch, coupled to a fully-automatic electronic control which handles the gear changes as selected by the driver. The gears are braked to a stand, changed and returned to full speed automatically, eliminating any risk of clutch burn.

The 12 and 16 gear mechanical gearboxes allow better matching of engine performance and speed across the range, improving fuel efficiency. Mechanical efficiency is particularly good at starting and at low speed. The unidirectional gearbox is coupled to a reverse shift gearbox in the axle-mounted final drive.

The electronic control system includes full diagnostics, using international standards for downloading maintenance information.

ZF Bahntechnik GmbH, Germany

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