an announcement from SEPTA:
Operations recently began on a pilot program at the Letterly Substation, where battery-like devices are capturing energy generated by Market-Frankford Line trains. The trains create energy during the braking process, and now, that power can be stored and put back to use on the line. This can help SEPTA reduce the amount of power it needs to purchase to power these trains – and also creates an opportunity to generate new revenue, as this captured energy can be sold on the power market. This pilot project was launched in partnership with Viridity Energy, which received a $900,000 state grant for the initiative.
Read more in today's Inquirer, "SEPTA is putting the brakes -- the El's brakes -- on wasted energy," by Andrew Maykuth 6/27/2012