Three seventeen-year-old Gold Coast boys are in a serious but stable condition after suffering burns from live railway lines.

A spokesperson from the Queensland Ambulance Service says the boys climbed on top of a railway barrier and were struck when electricity from the high voltage wires arched across to them.

The boys were found under a rail overpass, with two having 50 per cent of their bodies burnt and the third found with his heart racing at 175 beats per minute.