The document discusses the energy efficiency of railway transportation compared to other modes. It provides the following key points: 1) Electric trains have several advantages over diesel locomotives, such as regenerative braking and lack of idling time, making them more energy efficient. 2) While diesel locomotives have improved, over 90% of their operating time is spent idling unnecessarily. Electrified lines allow trains to operate more efficiently. 3) Trains are much more energy efficient than cars due to their greater mass and aerodynamics, which allows one locomotive to move hundreds of passengers using only 30% of the power needed for an equivalent number in cars.

1. How energy efficient really is
railway transportation?
Stefan Fassbinder
Deutsches Kupferinstitut
Am Bonneshof 5
D-40474 Düsseldorf
Tel.: +49 211 4796-323
Fax: +49 211 4796-310
sfassbinder@kupferinstitut.de
stf@eurocopper.org
www.kupferinstitut.de
www.leonardo-energy.org
The German Copper Institute, DKI, is
the central information and advisory
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2. Electricity boosts mobility
Electric motors
• have their highest torque at standstill:
No disengaging, no gearchange, no torque converter
required,
• provide a considerable short-term overload capability:
Higher acceleration than the power rating would let you
suppose,
• do not have any no-load consumption during standstill,
rolling or braking,
• offer the opportunity to feed back energy during braking!
Motor = Generator,
• and their primary fuel is totally flexible (fossil, nuclear,
hydro, wind – just mix as you like!).
So it is not a miracle
if railway companies prefer
electric traction!
Characteristic data of 16.7 Hz railways
Electricity system of DB AG
in D-A-CH
Installed Energy
Type of power plant DB AG ÖBB SBB
capacity production
Vapour 42.2% 66.0% Employees 240242 42893 27822
Hydro 11.0% 10.0% Passengers 1919Mio. 200Mio. 332Mio.
Railway grid
Rotating convertor 34.3% 14.6% total 33862km 11000km 3011km
Electronic convertor 11.9% 9.4% electrified 19300km 8200km 3011km
share
Total 3.2GW 11.0TWh/a of lines 57% 75% 100%
Sum of all electric vehicles 22.4GW (700%) of transport 85% 100%
volume
56% of DB lines are
… since the energy electrified. These 56% carry
“consumption” of an electric 85% of all traffic.
locomotive can be negative! However …
2

3. …what about the other 15%?
e. g. the
612 series?
• Engine power rating: 2*560 kW = 1120 kW
• Smart and convenient:
Tilting technique, air conditioning
• Maximum permissible speed: 160 km/h
• Fuel consumption: 1.7 l/km (for one, not 100 km!)
What about diesel locomotives?
• On a series 232 diesel locomotive (6 axles, 120 t,
2,200 kW, max. 120 km/h) at a constant speed of
120 km/h a consumption of 3 l/km was measured.
• (for good resons railway companies reference the fuel consumptions to
one kilometre, not to 100 kilometres!)
• There are no new diesel locomotives.
• There are old diesel locomotives with new engines.
•“Ludmilla” efficiency is then >40%.
The engine “Taiga Drum”
• But what„s the use of this if the engine is idling over 90% of its operating
time?
• And if a DB technician explains: “Diesel locomotives hamper the traffic
when circulating on an electrified line!” …
• …and if a railway trade journal reports the electrification of a line no
longer than 22 km had already cut the circulation time by 5 minutes?
„Elektrischer Betrieb bei der Deutschen Bahn im Jahre 2009“. „eb“ Elektrische Bahnen & Verkehrssysteme 1-2/2010, p.19
3

4. However, the 101 series electric loco
(4 axles, 84 t, 220 km/h) provides a
motor power rating of 6,600 kW!
Note: It„s electricity that wakes trains up!
The parameters responsible for
the energy demand are
(at ≈200 km/h): of a car of a train factor
(4…5 seats) (450 seats) 100
Mass 1.5 t 450 t 300
Note:of staticare a means of ≈55% transportation! 0.6
Coefficient Trains friction mass 28…35%
Coefficient of rolling friction ≈2% <2‰! 0.1
Resulting: some good reasons railwaykN
Note: For Rolling friction force 0.3 companies give rolling
9 kN 30
Power demand resulting from as per kW figures!
friction coefficients this 15 mille 450 kW 30
as a share of power rating 15% 7% 0.5
Air friction force 1.5 kN 30 kN 20
Power demand resulting from this 85 kW 1550 kW 18
as a share of power rating 85% 23% 0.27
Total power demand 100 kW 2000 kW 20
as a share of power rating 100% 30%! 3.3
4

5. Now what are the other
70% of power good for?
Compared to a car, a train has:
- A very great mass.
- Significantly less static friction
(steel on steel rather than rubber on asphalt).
+ Significantly less rolling friction
(steel on steel rather than rubber on asphalt).
+ Significantly less air friction (since the train
travels in its own windshade!).
Worth noting:
The top speed
of a car is usually of a railway vehicle
the highest is usually the
possible speed, highest
limited by the permissible
available engine speed.
power.
5

6. With a great deal of good will
66kW 6,6MW
we will now requirement car anda train
Power let a car with IC
•55kW kW engine and (very tight) space for
66 P (car)  5,5MW
P (IC train) 
•44kW
4 passengers travel at 4,4MW
•33kW km/h, P (car)
200 3,3MW
P (IC train)
while a train with a drive power rating of
22kW 2,2MW
• 6,600 kW offers plenty of space to
•11kW passengers (including toilets, a
400 1,1MW
bistro, …). At a travelling speed of 0,0MW
0kW
v 
• 200 km/h50km/h requires: 150km/h 200km/h
0km/h
this 100km/h
But a car accelerates faster?
100%
v/vmax 
90%
80%
70% Well, initially yes, but the
Acceleration process
60% car and trainlot … 200 km/h)
train has a (0 of reserves!
50%
40%
30%
20% v/vmax Car
10% v/vmax IC train
s 
0%
0km 1km 2km 3km 4km 5km 6km 7km 8km
6

7. Quiz question 1:
How far will an ICE2 express
train of the 402 series continue to roll
unbraked in a flat area when suddenly
the power fails at a speed of 230 km/h?
Answer 1:
The test was not carried out all through
to the end. After 32 km the train was still
rolling at 120 km/h!
Quiz question 2:
How fast will a railway carriage
become when you let it roll down a
decline of 5‰ (just 0.5%!)?
Answer 2:
Note: For some good reasons railway
companiesto technical documents by as
According give inclines and declines
per mille Bahn AG
Deutsche figures! it will (finally) reach
a speed of 44 m/s ≈ 160 km/h (after
1 hour of rolling)!
A street car would simply just stall and not roll at all!
7

8. Quiz question 3:
Why is it that in a train repair
hall which can be opened at both ends
it is not allowed to leave both gates
open at the same time?
Answer 3:
Because the wind might blow the
locomotoves out of the hall!
So let’s just accelerate a
200km/h
fully occupied street car
v 
to 200 km/h, disengage
150km/h
and see what will
happen…
100km/h
Mass: Train rolls kg
2000
Train rolls
Train brakes
Car rolling out
Rolling friction coefficient: Car rolling out
50km/h
2%
Car rolling out
Front surface area: 2 m²
cx value:
0km/h 0.37
2km s 
Engine power: 1km
0km
105 kW 3km
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9. Hauling force and power
IC fast train with DB's 101
300kN series locomotive and 6MW
9 carriages
250kN 5MW
Hauling force 
Power 
200kN 4MW
150kN 3MW
Required hauling force
Required power
100kN 2MW
50kN 1MW
Speed 
0kN 0MW
0km/h 50km/h 100km/h 150km/h 200km/h
Hauling force – 80% left?
IC fast train with DB's 101
300kN series locomotive and 6MW
9 carriages
250kN 5MW
Hauling force 
Power 
200kN 4MW
150kN 3MW
Required hauling force
Available hauling force
100kN 2MW
Required power
50kN 1MW
Speed 
0kN 0MW
0km/h 50km/h 100km/h 150km/h 200km/h
9

10. Power – 70% left?
IC fast train with DB's 101
300kN series locomotive and Power limit 6MW
9 carriages
250kN 5MW
Static friction limit 
Hauling force 
Power 
200kN 4MW
150kN 3MW
Required hauling force
Available hauling force
100kN 2MW
Required power
Available power
50kN 1MW
Speed 
0kN 0MW
0km/h 50km/h 100km/h 150km/h 200km/h
At 300 km/h, however …
300kN 8MW
ICE3 high speed railcar
of DB's 403 series 7MW
250kN
… the demand does 6MW
F 
200kN increase rapidly  5MW
150kN 4MW
P 
Required hauling force
3MW
100kN Available hauling force
Required power 2MW
50kN Available power
1MW
v 
0kN 0MW
0km/h 100km/h 200km/h 300km/h
10

11. The ultimate train concept
330km/h ICE3 high speed railcar 0,75m/s²
a 
300km/h of DB's 403 series
270km/h 0,60m/s²
240km/h
210km/h 16 out of 32 axles driven 0,45m/s²
180km/h
v 
by a 500 kW motor each
150km/h provide optimal
0,30m/s²
120km/h acceleration and
90km/h energy recovery
60km/h 0,15m/s²
Speed
30km/h Acceleration
s 
0km/h 0,00m/s²
0km 5km 10km 15km 20km 25km
The ultimate train concept
330km/h ICE3 high speed railcar 0,75m/s²
a 
300km/h of DB's 403 series
270km/h 0,60m/s²
240km/h
210km/h 16 out of 32 axles driven 0,45m/s²
180km/h
v 
by a 500 kW motor each
150km/h provide optimal
0,30m/s²
120km/h acceleration and
90km/h energy recovery
60km/h 0,15m/s²
Speed
30km/h Acceleration
t 
0km/h 0,00m/s²
0s 60s 120s 180s 240s 300s 360s
11

12. Also you have to accelerate the train to
the desired travelling speed of 300 km/h
(83.3 m/s) first in order to run that fast
With a 4% supplement for rotating masses and an efficiency
of 87%, measured at the pantograph, this makes about
520 kWh for one single acceleration from 0 to 300 km/h.
With the DB tariff of 9 c/kWh this costs approximately 47 €!
It would be pretty sad to get nothing of this back at all.
Counted with an efficiency of 87% again, you can retrieve
75% during brakage – if all goes well.
2
m 450 ,000 kg m
Wkin * v² * 83.3 1.56 *10 9 Nm 1.56GJ 434 kWh
2 2 s
Bad outlook for the diesel
Electric traction turns out to be far superior:
• Power density and dynamic behaviour are outstanding.
• 8% of all electricity consumed by locomotives in Germany
has been used once before by another locomotive and fed
back again into the supply system.
• Usually this works only with water (or e. g. copper!) but
never ever with coal, gas and oil.
• The share will continue to grow, since by and large more
and more old electric locos without feedback capability are
being replaced with modern power electronic ones.
• But we will still have to wait for a long time to see a diesel
engine coming around that, when braking, sucks up fumes
and converts them back into fresh air and fuel.
12

13. Electric power speeds us up!
• For 2009, DB„s department for Energy Cost Management
gives an average circulation of 347,620 km for each of their
145 locomotives of the 101 series.
• The average consumption is ≈17 kWh/km (including
electricity the locomotive has fed into the train for heating
the carriages and for ancillary supplies).
• This yields an electricity cost of half a million Euros per
year.
• The purchase price of the 101 series is around 3 million
Euros.
• So for the power consumption of a locomotive„s 30-year-
long life you could buy in 5 complete locomotives!
• 8% of energy fed back saves 1.2 million Euros per loco
during 30 years!
Or let’s have a look at
suburban transportation
The regional train from Aachen to Dortmund
travels about 160 km far, calling 22 times.
Its top speed is 140 km/h.
If it went all through non-stop, it would consume
only 800 kWh for overcoming the friction.
But accelerating 22 times costs 1600 kWh!
So this is 2/3 of the overall energy consumption!
Hence, in theory about 3/4 out of 2/3, say half of the
energy, could be recovered, but unfortunately …
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14. Or let’s have a look at
suburban transportation
… according to DB Regio the real rate of recovery
is only 10% in this business unit!
And now what to do? What’s the deficiency?
Hence DB’s plans for the
coming decades are:
• Increase the share of inverter 10% → 20%
locos from 47% (2009) to 100%
• Improve control infrastructure – 20% → 50%
no more odour of hot brakes
• Replace all Loco-and-carriage 50% → 60%
trains with railcars, since:
• Railcars are lighter and hence use less energy
• The dispersed drive expands the opportunities
for energy recuperation
14

15. Now what„s up with
the 44% of lines
without a trolley wire?
• There is a diesel railcar standing at the railway station. There are 2
engines mumbling under no-load conditions inside it – and are being
cooled, while an oil heater fuelled with diesel fuel at the price of diesel
fuel is heating the passenger cabin.
• The railcar starts. The engines raise their voices a little bit.
• Only above some 30 km/h … 60 km/h the full power can be transmitted
to the rails: Now the engines hum a bit more vigorously – for about one
minute. Then the top speed has been reached. About 30% of the
engine rating suffice to sustain a constant speed of 160 km/h.
• But very soon we are approaching the next station. The railcar is kept
rolling for several minutes, the engines disengage, mumbling calmly.
• Then the railcar brakes. The engines rev up – just to dissipate the
heat from the hydraulic braking system via the engine radiators!
Is this a concept for the future? – Or rather a makeshift solution?
But wasn‘t there something else?
Oh, right: The 515 series!
• Accumulator-operated railcars
have been in use since 1907!
• for 40 years, from 1955 to 1995, well over 220
motor vehicles of the 515 series have been in use:
• Power rating 2*150 kW
• Maximum speed 100 km/h
• 10 t … 16 t of lead accumulators
• Capacity 352 kWh … 602 kWh
• Cruising range 300 km
15

16. Mental experiment:
A modern re-issue
• Today„s Li ion accumulators provide 4 times the
energy density of the old lead acid batteries, so:
• you can double the capacity while halving the
mass.
• Doubling the capacity doubles the cruising range
to about 600 km.
• halving the weight along with the use of modern
inverter technique with generative brakage im-
prove the performance (min. 140 km/h) and the
comfort (e. g. air conditioning).
Comparing a hypothetical electric
battery railcar to a street car
Tesla Electric
Roadster railcar
Energy capacity 55 kWh 1100 kWh
Energy demand 200 Wh/km 2000 Wh/km
Energy demand per seat 100 Wh/km 10 Wh/km
cruising range 350 km 600 km
Battery mass 0.45 t 9t
as share of the vehicle 36% 12%
Battery price 45.000 € 900.000 €
as share of conv. vehicle 50% 25%
16

17. How much really is the
electricity from the battery?
Battery price: 900.000 €
Life time: 3000 cycles
Energy capacity: 1100 kWh
So in effect the power from the battery costs:
Electricity taken from trolley wire 90 €/MWh
Charge cycle / conversion losses +10 €/MWh
Night tariff rebate -10 €/MWh
Wear of the accumulator battery +270 €/MWh
Electricity cost from the battery 360 €/MWh
Comparison to the existing
series 612 diesel railcar
Diesel railcar Batt. railcar
Primary energy demand 20 kWh/km <6 kWh/km
Secondary energy demand 17 kWh/km 2 kWh/km
(1.7 l/km)
Net energy price 1.03 €/l 0.09 €/kWh
Energy price from the battery – – – 0.36 €/kWh
Net energy cost 1.80 €/km 0.18 €/km
Energy cost incl. battery – – – 0.72 €/km
At 250,000 km/a 450,000 €/a 180,000 €/a
During a 30 years„ life 13,500,000 € 5,400,000 €
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18. Alternative 1: Accumulator
railcar with pantograph
Local trains often leave
the city centres on
electrified lines and turn
off onto the seconday
lines only a bit later on.
Here the vehicles could
• be charged up during ride
• in part be driven as conventional electric railcars
with pantograph (»pop-up hybrid«)
• and thus require only a fraction of the (expensive)
battery capacity.
Alternative 2:
Hybrid diesel railcars
Do not confuse with the principle of the diesel-
electric locomotive! Since this is an electric locomotive lugging around
its own power plant
• With the hybrid railcar, however, the diesel engine has only some 10%
of the electric power (e. g. a 66 kW car engine instead of 2*315 kW
railway engines).
• For the diesel engine is always running at the optimal point of operation
(rated speed and power) instead of idling ≈90% of its time.
• Also the generator rating is only 10% that of the electrical traction
power.
• The battery provides 90% or bears 110%, respectively, of the electrical
traction power during acceleration and brakage, respectively.
• Continuous heat generation. Combined heat and power generation
replaces the oil heater.
• Facilitates combination with alternative 1.
18

19. Hybrid diesel railcars – also
for long-distance fast trains?
Just take a trip from Berlin to Copenhagen!
There they are using up the unfortunate series 605 now.
• These railcars are equipped with diesel-electric drives, so
these already avail of electric drive motors and inverters.
• These trains arose on the platform of the 415 series 5-
carriage electric railcar!
• They had been withdrawn from service for several years.
• They were offered for sale, but nobody wanted them.
• One of the reasons given for the latter two points are high
fuel costs.
So why not convert these trains first?
Series 605 – ICE without pantograph
Just consider:
• Here the train does not run very fast and rarely stops.
• Still the fuel consumption lies around 3 l/km!
• This costs around 1800 € per single trip
• For this alone 7 full-charge or 45 low-cost ticket passengers
will have to be sitting on the total of 195 seats
• Whereas the major share of the easement is electrified!
• And for one hour the train is not travelling at all but is
standing on a ship.
So why not
• remove 3 of the 4 diesel engines and generators,
• replace them with accumulator batteries,
• possibly add a pantograph and a transformer
• but in any case reduce the fuel consumption by 1 l/km
• and save about 600 € of fuel cost on one trip?
19

20. Summary and conclusions
• Electric railway drives clearly outperform diesel
engines.
• At the same time electric railway drives are way more energy efficient
than diesel traction is.
• SBB operate 100% electrically – nothing left to do.
• E. g. DSB are 27% electrified – need for action!
• DB AG operate 85% electrically – this is fine so far.
• For the remaining 15% a re-introduction of battery operated railcars
based on modern lithium ion cells should be considered. 40 years of
good experinece even with lead acid accumulators support this idea.
• The economic viability of electric cars lies about 10 times further
away from reality than that of the battery operated railway vehicle!
The German Department of Technology and the EU Commission
should urgently take this into consideration with their energy efficiency
support programmes.
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