My talk to the IMechE Railway Division on failure regimes on pantographs, and the relevant mitigation plans to address these problems.

1. Pantograph
Failure &
Analysis
for the IMechE “Future of Rail”
Network Rail, Swindon – 14th March, 2016
presented by
Kelvin Lam
2nd Year, Mechanical Engineering Student
University of Bristol

2. Why…?
• Extensive rail upgrade works around the UK
• Insufficient studies on failure
• Rolling stock downtime (Cost to TOCs + KPIs!)
• Catastrophic consequence (passengers,
workers, surroundings)

3. Maintenance criteria
RAMS
• R eliability
• A vailability
• M aintainability
• S afety

4. Failure overview
1. Material fatigue 2. Acoustic factor

5. Material fatigue – 1/2
• Impurities in
surroundings
• Dislocations
• ↑ surface area
• Non-linearity in
dislocations

6. Material fatigue – 2/2
• Zig-zag catenary ...
Concern:
probability of wire
contact
• Electric arc
flashover: 19273
kelvins – ionisation!
 Effect: dent on carbon strip

7. Acoustic – 1/3
• Pantograph + OHLE
= coupled system
• Large pantograph
structure

8. Acoustic – 2/3
OHLE-induced causes
• 3 types: simple, compound,
stitched
• Self-excitation: wind factor,
Q-factor

9. Acoustic – 3/3
• Rolling friction (elastic
deformation)
o Compression towards
centroid of wire
(contact theory)
o Disturbed stress field:
different stress =
different energies at
different locations

10. Effects on acoustic factor…
1. stress cycle
2. structural load
3. intermittent contact

11. How to mitigate them? (Overview)
Maintenance
Preventative > Corrective
Inspection
• Strain gauge/monitor
(existing Panchex)
• Trackside camera
(PantoInspect)
• Ricardo’s PanMon

12. How to mitigate them?
Force approach:
Network Rail –Panchex
• Deduce
tensile/shear stress;
uplift force
• Detect and respond
to irregularities
(ADD)
• Ineffective!

13. Too many…
numbers!
(but meaningless…)

14. Too many…
numbers!
(but meaningless…)

15. • Hierarchy diagram of Siemens SICAT Pantograph
Monitoring System (PMS).
REPORT
FEEDBACK

17. © Ricardo Rail (Nov 2015)

18. Conclusion
• Maintenance: crucial for safety & KPIs
• Causes: materials & acoustic
• Result: egregious system interface issues
• Panchex is obselete
• Trend now: PanMon/PantoInspect

19. Thanks for your attention.
Any questions?
Kelvin Lam
2nd Year, Mechanical Engineering student
University of Bristol