Employing regenerative braking in trains can lead to substantial
CO2 emission reductions, especially when applied to full stop
service commuter trains (8 – 17%) and to very dense suburban
network trains (~ 30%). Regenerative braking applied to freight
trains can also lead to CO2 emission reductions, albeit
considerably lower than for full stop service trains (~5%). When
regenerative braking is employed, the current in the electric
motors is reversed, slowing down the train. At the same time,
the electro motors generate electricity to be returned to the
power distribution system. Regenerative breaking is a mature
technology. It can be more easily applied to AC powered trains
than to DC powered systems. In DC powered railway systems
usually higher investment costs are needed. A conventional
electric train braking system uses dynamic braking, where the
kinetic energy of the train is dissipated as waste, mainly in
the form of heat. When regenerative braking is employed, the
current in the electric motors is rever