Keeping trains on track

10 September 2015

Industrial safety specialist Castell has supplied a customised trapped key interlocking system to Bombardier Transportation to safeguard shore supply maintenance operations on ELECTROSTAR trains.

The safety system is fitted to all Bombardier ELECTROSTAR trains, produced for Southern Railways, South Eastern Trains and c2c.


"Castell has been supplying trapped key interlocking systems to Bombardier for 15 years," Guy Heywood, commodity buyer at Bombardier Transportation, said. "We chose Castell for this project because we needed a high-quality technical solution that met specific requirements at a competitive price."

Each safety system comprises a shoe gear earthing switch interlock and a shore supply socket interlock, both of which are mounted on the train carriage. To connect the shore supply maintenance cable to the shore supply socket on the carriage, all shoe gear earthing switch interlocks must be moved from the ‘normal’ to the ‘shore supply’ position. This action releases a Castell key from the shoe gear earthing switch interlock – the key is trapped when the switch is in the ‘normal’ position – which is inserted into the shore supply socket interlock, along with all the keys from the other shoe gear earthing switch interlocks. The shore supply maintenance cable can then be inserted. The keys cannot be removed until the cable has been disconnected, thus ensuring safe operation.