"Fortescue Metal Group's Infinity train will never need to be fuelled, never need to be charged... it uses regenerative braking to charge onboard batteries when

"Fortescue Metal Group's Infinity train will never need to be fuelled, never need to be charged... it uses regenerative braking to charge onboard batteries when it goes downhill and uses that charge to get back up the hill. Does that sound like a perpetual motion machine to you? The project doesn't actually rely on a secret source of "free energy" to work. Sorry if that disappoints you! It's all based on sound physics, which I explain in this video and then I run the calculations to see whether the numbers add up!"