Railways

Copper in locomotives

When you look inside an AC locomotive, you may notice that there is a transformer in it. You may figure out that the rating of said transformer is ≈5 MVA, its efficiency is ≈95% and the mass ≈10 tons. A utility transformer of comparable rating (same frequency – the odd 16.7 Hz in Germany, Austria, Switzerland, Norway and Sweden) would have a mass of 50 t and an efficiency of 99%.

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Railway power supply

What is this? A copper bonanza. While in West Germany and Switzerland the 16²/₃ Hz single-phase railway power supply has always been powered prevalently from dedicated power plants (with a much higher share of hydro power than the public supply includes, by the way) or from separate generators in existing power stations, in East Germany nearly all railway power was taken from the public grid.

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Ancillary consumption of railways - heating 2

Diesel fuel and heating oil are chemically identical. »Only« the tax rate the final consumer has to pay is (very much) different. But obviously the difference looks a lot different for railway fuel, i. e. the difference makes no difference there. This smart, modern German railcar of the Baureihe 612 series (google for »BR 612« for photos), which comes as a twin carriage (4 bogies / 8 axles) with 2 diesel engines (of 560 kW each!), has 2 separate tanks for engine fuel and for heating oil. But obviously it doesn’t matter what you fill in where.

If you have had the opportunity to join a locomotive driver on the predecessor, BR 610, then you may have seen that this series still used to have an engine power indicator, which was omitted later in the 611 and 612 series, and that the full power (»only« 2*525 kW on the 610 version and 2*540 kW on the 611 version) is only used for accelerating the weighty vehicle and for travelling uphill. To sustain its constant maximum permissible speed of 160 km/h in the plains an engine power output level of ≈35% is enough. Several kilometres before the next stop the locomotive driver disengages the engines, and the railcar rolls and rolls and rolls, you just don’t realize any drop in speed. Then the brake is operated, the train brakes and brakes and brakes, while the engines keep on running with their (though low – but technically at least during these stages totally avoidable) stand-by loss. But the »waste« heat is needed for the passengers inside – while simultaneously the brake disks need cooling.

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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.

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Railway earth (2)

…when DC and AC powered railway lines are paralleled, such as here in Berlin Spandau station (and all across Berlin). It came as a great surprise, even to one of the so-called harmonics gurus, when he was measuring the no-load power intake of a 200 VA toroidal core transformer and turned on a hot air blower to half power on the nearest socket.

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