• Trains can use power more efficiently when the energy generated from braking can be redistributed into the power grid, and new smart grid advancements are making that possible.
• The Southeastern Pennsylvania Transportation Authority (SEPTA) has a pilot project seeking to better absorb and reuse brake energy.
• SEPTA uses a battery system and feeds power back into the regional transmission organization, after which the energy can be sold to neighboring power grids.

From the article:

Electric commuter trains, while quiet and fast, have one glaring inefficiency – when they brake at a station, the energy of the moving train is lost, even when the motors are electrically reversed. Capturing the electrical energy generated during braking is simple, but efficiently redistributing it through the power grid is not. The result, in too many systems, is that the braking energy is simply wasted. Now an energy storage project in Philadelphia aims to capture and efficiently utilize that braking energy, providing a clear view into the potential of the forthcoming smart grid. ...