But Vycon’s systems are different. Unlike many existing transport systems, it does not use onboard flywheels. Instead, the flywheels are used to store energy trackside at each station, meaning there are fewer limitations on size, and the weight of the device does not have to be transported.
“It reduces the overall energy consumption of the station, and also the peak power demand,” according to McMullen.
The LA trial, for example, will collect power generated by braking trains that enter the Westlake and MacArthur Station. It will store 2MW, with flywheels designed to fit into the existing electricity substation. The power storage unit consists of 4 modules, each containing a high-speed steel flywheel and a motor/generator. Each one is about 0.9m by 1.2m (3ft by 4ft).
Over the next year, the company hopes to work with other transport agencies around the world to install other demonstrations of its technology. McMullen sees a future where flywheels are not only installed in existing public transport systems, but designed into it from the start.
“When you build out new systems you look at putting a substation every mile. Now, you can alternate between putting a substation and a flywheel, so that you can end up having a reduced overall cost. You don’t have to drop your power lines every mile.”
Retrofitting existing tracks is likely going to be an expensive business, meaning the first full-scale use of flywheels will be in those emerging economies – like China and India – where there is the room and money to build new transit systems.
If and when they get built, passengers may not know – or care - that their train is running on steam age technology. But its effects will be seen. As well as saving money for the public purse, flywheels have one last trick up their sleeve – they could allow trains to run more quickly, regularly and smoothly.
Currently, train departures are – in part – managed by their power demands. Less frequent or staggered trains do not put unnecessary loads on the system. Add a flywheel and you have a cheap energy supply that can provide a boost when it is most needed, potentially allowing more trains to run simultaneously and pull out of the station more quickly.
So, in the future, that rush hour crush may be just that little bit more bearable. And it could be thanks to a technology that has been in use since the steam age.