 The foundation used for the pylons is of the "Hang-dug Caisson" type.Each pylon is founded on four Caissons measuring 1.2 metres in diameter, which are socketed down to bedrock.The average depth of the Caissons is about 40 m (135 feet) and each group of four Caissons piles can take a vertical load of 4,000 tonnes against the maximum vertical load of 150 tonnes from the cable car system.