The APS units, which are enclosed and mounted beneath the cars, are cooled naturally and incorporate a dc-dc power module which uses Silicon Carbide (SiC) technology in order to sustain high voltages and be switched at high frequency. This allows the units to be smaller than previous designs and to operate more reliably.


The units have an intelligent monitoring system which records events and conditions, while portable test equipment software will enable maintenance staff to diagnose faults.

Turbo Power Systems and Bombardier have been working to develop the new APS units during the last two years, and the contract with Bombardier will run until 2024.