Ancillary consumption of railways

When you are lucky enough to have the insight into the interior technical details of a German ICE 2 high-speed railcar, you may realize that the main transformer has 7 output windings. Next to 4 windings with a 1 MVA output for the 4 inverter drives, you will find 3 windings for ancillary supplies, among them one for the carriage heating with an output rating of 500 kW!

But also without such opportunities, you only need to look around at the railway stations, and you will find quite a number of connection points for train pre-heating. Since most passenger trains in Germany are either operated electrically or they come as railcars with integrated diesel engines, these connection points are mostly no longer in use today (as the label tells you here for example). But note that the voltage ratings are 1500 V, 2000 V or 3000 V! This is not done for fun but because the heating of (especially old) trains guzzles tremendous lots of energy. This remains to be included into considerations about how to make railway transportation even more energy efficient, which despite all it already is, but there are still significant potentials left.