Project: Waratah Earth Switch

Award Winning Advanced Safety System. High Current, High Voltage.

The Earth Switch project was conceived in 2008. Australian Rail Technology was approached by Downer EDI Rail to create a new product that had never been fitted to a train in Australia.

Review our award here, on the Sydney Trains website, under the heading “Engineering and Projects Group”.

A$4.5 million, 35 year support contract

At a value of A$4.5 million, we were asked to design, test and manufacture a 1500 VDC 2000 amp earthing system for the new Waratah trains (78 set fleet of A-set trains), 936 units in total (4 earth switches and 8 junction boxes per 8-car set).

The function of the Earth Switch, that is manually operated and locked by maintenance workers, is to provide an added level of protection to ensure that all HV circuits of the train are earthed during works.

The core switch mechanism was based on an existing ART outdoor-type DC isolator, reconfigured to fit within a small frame-mount enclosure.

Features:

  • Dual contacts to simultaneously earth the main and auxillary HV circuits
  • Rating of IP65, impact resistant stainless steel enclosure, 45 kg
  • 30 micro-ohm contact resistance
  • Mechanically interlocked access panel
  • Auxillary contacts interface with high speed circuit breaker, panograph and eTIS
  • 35 year design life
  • 5000 page documentation pack

Testing completed and accepted by Sydney Trains:

  • IP65
  • Shock and vibration to IEC61373, Category 1, Class A
  • General performance (cycle testing, environmental testing to -5 to +45 deg C, full current temperature rise, dielectric and insulation)
  • Fault current withstand (full load of upstream breaker 1500 VDC at 40,000 amps for 13 ms)
  • Insulators to AS/NZS3121:2000
  • Resistance to vandalism and graffiti
  • On-train integration testing
  • The contract was signed Jan 2009 and manufacturing was completed May 2011