Cave train role

The operators needed the transport method to be energy efficient and quiet to run. Together with Sentridge Control, Severn-Lamb designed a propulsion system for an electric train that would run along a 700m track, with 100m being within the cave itself. Capable of carrying 48 passengers, the train takes three-phase, 415V power from an electrified third rail and can travel at up to 20km/h.

Glen Hickman of Sentridge Control says: "The drive solution was designed to be redundant so that if we lose one motor, the train can still keep driving. Another feature of the solution is the communication capabilities of the drives. A built-in drive-to-drive link allows the drives to talk to each other, via a master-follower arrangement, enabling them to run at the same speed and share the load.”

The drives allow the train to be driven from either end by transferring the master drive function to the rear most drive. Another feature that could be used in the future is the ability for the drives to receive a signal from an external pick up mounted on the train, allowing them to detect points and reduce speed accordingly.

The drives need to operate in an ambient temperature that can reach 50°C. Severn-Lamb worked with Sentridge Control to devise a cooling system that feeds air to the drives from the main cab air conditioning system.