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New Concept for Higher Speed on
Existing Catenary System:
Auxiliary Pantograph Operation
Zhendong Liu, Sebastian Stichel, Per-Anders Jönsson
KTH Royal Institute of Technology, Sweden
Anders RønnquistNTNU Norwegian University of Science and Technology, Norway
BACKGROUND
Background
High dynamic load in the contact
between pantograph and catenary:
• Stiffness variation in a span
• Wave propagation
Reasons for contact force variation
and high dynamic load:
• Low quality of current collection
• Excessive mechanical wear
• Electromagnetic interferences
• Even structural damage
Background
Solutions for higher speed
• Low stiffness variation
• High tensile force
• Damping or pre-sag
• High-speed pantograph
• Actively-controlled pantographTable 4.1: Tensile force applied to high-speed catenary systems [46]
Country System Operational speed Tensile force on contact wire Tensile force on catenary wire
Sweden SYT 15/15 250 15 kN 15 kN
Germany Re 330 330 27 kN 21 kN
France Atlantique 320 20 kN 14 kN
Italy Rom-Neapel 300 20 kN 16.25 kN
Spain Madrid-Lerida 350 31.5 kN 15.75 kN
Japan* Osaka-Hakata 300 19.6 kN 24.5 kN
China Beijing-Shanghai 350 31.5 kN 20 kN
* Compound catenary system: the tensile force on the auxiliary wire is 14.7 kN.
Long out-of-service time
& Huge investmentStrength limit of material
in the future
Complicated system
& deterioration trend
Background
One possible solution for higher speed
- Easy to implement on the existing pantograph-
catenary system.
- Short out-of-service time and low investment.
- Not limited by material strength.
Demand
Auxiliary Pantograph OperationA pantograph is designated to create a favourable
working condition for the main working pantograph.
SIMULATION TOOL
Simulation tool
Simulation based on the finite element program
ANSYS and a 3D pantograph-catenary modelSide view:
Top view:
Stitch wireCatenary wire
Contact wireDropperSteady arm
Lateral stagger
Steady arm
Track centre line
Contact wire
m1
k2
c1
k1
m3 m2
c2
d2d1
c3
f3
kf3
Contact element
m4
L
x
• Contact strip perpendicular to running
direction to show lateral stagger
• Droppers insulating the axial
compression force to express dropper
slackening
Schunk WBL88
pantograph
Description of
system
parameters:
Simulation tool
In the following part, the
standard deviation is
regarded as a key
indicator to evaluate the
quality of pantograph-
catenary interaction.
BENEFICAL EFFECT
Two-pantograph operation at short spacing:
The meshed area marks the cases where the leading or
trailing pantograph works even better than in single
pantograph operation at 200 km/h
What can cause this?
Leading Trailing
Beneficial effect
Investigation
Pantograph: WBL 88
Catenary: SYT 7.0/9.8
Running speed: 200 km/h
Speed: 180 - 280 km/h
Spacing: 30 – 120 m
Proper excitation
Two-pantograph vs Single-pantograph
30 40 50 60 70 80 90 100 110 1205
10
15
20
25
Spacing distance (m)
Sta
ndard
de
via
tion (
N)
Leaading
Trailing
Single
300 330 360 390 420 450 48040
60
80
100
120
140
160
Longitudinal location (m)
Co
nta
ct f
orc
e (
N)
Leading
Trailing
Stiffness0.4
0.6
0.8
1
1.2
1.4
1.6V
ert
ical st
iffn
ess
(N
/mm
)
At 40 m
Beneficial effect
-20 0 20 40 60 80 100 120-0.05
0
0.05
0.1
0.15
Distance after pantograph passing-by (m)
Ve
rtic
al dis
pla
ce
ment
(m)
Point A (-4.5 m)
Point B (0 m)
Point C (+4.5 m)
Point D (+9 m)
Point E (+13.5 m)
Possible place to
introduce an
additional trailing
pantograph
A B C D E
• Meeting a downwards-moving
catenary to acquire additional
compressive force where the
contact is soft
Wave interference
0 0.5 1 1.5 2-5
0
5
Time (s)
Mag
nitude
of
wa
ve (
cm
)
Wave 1
Wave 2
Resultant wave
0 2 4 6 8 100
5
10
15
20
25
Frequency (Hz)
Am
plit
ud
e (
N)
Single-pantograph
Trailing - Spaced at 40 m
0 2 4 6 8 100
5
10
15
20
25
Frequency (Hz)
Am
plit
ud
e (
N)
Trailing - Spaced at 60 m
Single-pantograph
Frequency analysis of contact force
600 660 720 780 840
0
0.05
0.1
0.15
Longitudinal location (m)
Ve
rtic
al dis
pla
ce
ment
(m)
40 m
Wave Interference
Wave propagating speed C
𝑓𝑝 =1
𝑇𝑝= 𝑣 𝐿=0.93 Hz
What can change
this frequency?
𝑓𝑐 = 𝛼 ∙ 𝑓𝑝 =𝑐
𝑐−𝑣∙ 𝑓𝑝=1.86 Hz
Propagating wave
interference
Two oscillating
sources at nearly
the same frequency
Beneficial effect
Leading
Trailing
Normal two-pantograph
operation at high speeds
Overcome electrical wear by no electric load
Electric load
Soft contact
+ Arcing Wear
Overcome mechanical wear by low uplift force
30 40 50 60 70 80 90 10010
12
14
16
18
20
Percentage of the normal contact force applied (%)
Sta
ndard
de
viation (
N)
Trailing pantograph
Single pantograph at 200 km/h
Single at 200 km/h V.S.
Trailing at 260 km/h
Uplift force reduction of
the leading pantograph
can improve the dynamic
performance and reduce
the mechanical wear.
Leading panto. as auxiliary panto.
serves the trailing panto.
Auxiliary pantograph operation
480 495 510 525 540
50
100
150
200
Longitudinal location (m)
Co
nta
ct f
orc
e (
N)
Single
Leading - normal
Trailing - normal
Leading - reduced
Trailing - reduced
IMPLEMENTATION
Implementation
Using two pantographs together &
Taking one of the pantographs as
auxiliary pantograph .
Auxiliary pantograph operation
Similar application – Bulbous bow
• Increasing speed
• Reducing fuel-consumption
• Enhancing stability
Big front nose
Switch it off from Circuit
Sensitivity investigation
VariableRatio of
deviation
Result of the trailing pantograph
Mean contact
force (N)
Standard
deviation (N)
Percentag
e
Spacing
distance
40 m
-5% 133.26 15.09 +10.8%
+5% 133.62 13.58 -0.3%
Tension force
7 kN, 9.8 kN
-5% 134.28 14.78 +8.5%
+5% 132.67 13.39 -1.7%
Uplift force
65.16 N
-5% 133.20 13.74 +0.9%
+5% 133.53 13.69 +0.5%
Damping ratio
0.02
-5% 133.37 13.58 -0.3%
+5% 133.35 13.63 -0.1%
Mass of pan-
head
6.6 kg
-5% 133.24 13.51 -0.8%
+5% 133.36 13.73 +0.8%
Stiffness of
pan-head
4400 N/m
-5% 132.53 13.05 -4.2%
+5% 134.08 14.18 +4.1%
Normal value 133.34 13.62
.
5% deviation of some key parameters
540 570 600 630 660
60
100
140
180
Longitudinal location (m)
Ve
rtic
al dis
pla
ce
ment
(m)
Low damping
Leading
Trailing
540 570 600 630 660
60
100
140
180
Longitudinal location (m)
Ve
rtic
al dis
pla
ce
ment
(m)
High damping
Leading
Trailing
(a) (b)
The contact forces with low damping
ratio of 0.5% and 5% at 260 km/h.
The system is not very sensitive
to parameter deviation.
Pantograph raising and lowering:
Emergency and Special section
• Train passing through special sections
• Emergency condition. i.e. obstacle on catenary
• Other unfavourable working conditions
4 6 8 10 120
50
100
150
200
Time (s)
Con
tact fo
rce (
N)
40 m
Auxilary
Trailing
4 6 8 10 120
50
100
150
200
Time (s)
Con
tact fo
rce (
N)
60 m
Auxilary
Trailing
40 m
60 m
4 6 8 10 120
50
100
150
200
Time (s)
Con
tact fo
rce (
N)
middle v200
Auxilary
TrailingAt 200 km/h
2 4 6 8 100
50
100
150
200
Time (s)
Con
tact
forc
e (
N)
middle
Auxilary
Trailing
At 260 km/h
At certain speed the
auxiliary pantograph can
smoothly get into force.
Spacing distance is
important &
improvement is seen.
CONCLUSIONS
Conclusions
• Taking one of pantographs on trainset as auxiliary
pantograph is a feasible solution for speed-increase
on existing railway system.
• Poor dynamic performance and excessive wear can
be avoided by reduction of uplift force.
• The system is not very sensitive to small parameter
deviations.
• Unfavorable working conditions can be avoided by
pantograph raising and lowering operation.
Future work
• Investigations of the relationship between the
response of the catenary after pantograph
passing-by and some other parameters
• Further parametric studies taking into account
factors such as disturbances, structural errors
and special sections
A better understanding can help to find
more technical solutions.
