1. Guidance for rail grade selection
STE-PR V/T SIC seminar
Guidance for rail grade selection
Mark Burstow
Principal Vehicle Track Dynamics Engineer
December 2017
December 2017

2. Background Part of V/T SIC’s strategic objectives:
STE-PR V/T SIC seminar
Background
Part of V/T SIC’s strategic objectives:
Reduce ‘stress state’ of rail
Increase stress tolerance
Introduction of alternative grade rails to combat wear and RCF
Increasing ‘stress tolerance’ of system
Improving rail management strategy
To achieve this
Need good guidance for designers and track engineers for selecting appropriate rail grade for given situation (curvature, cant deficiency, vehicle type (PYS))
Track-Ex can be used- currently being more widely used in new designs
More general guidance would be useful
Does not require detailed modelling
December 2017

3. Existing guidance NR/L2/TRK/2102 Section 9: specification of rails
STE-PR V/T SIC seminar
Existing guidance
NR/L2/TRK/2102
Section 9: specification of rails
Not clear where they should be used
December 2017

4. Existing guidance TWI From 2005!
STE-PR V/T SIC seminar
Existing guidance
TWI
From 2005!
Before most recent developments in rail grade
Before Track-Ex and other tools to help with damage prediction
Guidance aimed at rail wear
Not RCF
Consider lubrication as an alternative to changing rail grade
Consider other problems it may generate
e.g. weldability
December 2017

5. STE-PR0033-00093 V/T SIC seminar
INNOTRACK
December 2017

6. STE-PR0033-00093 V/T SIC seminar
INNOTRACK guidelines
December 2017

7. 250m radius curve example, ‘normal’ grade rail
STE-PR V/T SIC seminar
250m radius curve example, ‘normal’ grade rail
Site has history of low rail RCF
Spalling and cracking
Rail was 5 years old
Frequent grinding to restore low rail profile due to surface damage and plastic flow
No RCF or damage on high rail of curve (9 years old)
December 2017

8. Comparison of premium and normal grade rail (9 months in service)
STE-PR V/T SIC seminar
Comparison of premium and normal grade rail (9 months in service)
Low rail
Premium grade rail showed no plastic flow towards the field side
Premium grade rail did not develop low rail RCF
High rail very similar shapes
Both rails protected with lubrication
Low rail
High rail
December 2017

9. High rail condition: a surprising effect
STE-PR V/T SIC seminar
High rail condition: a surprising effect
6 weeks after installation RCF was observed on high rail, where there was no damage previously:
Harder grade rail had been expected to be more wear & RCF resistant, prolonging the life of the low rail
RCF developed closer to gauge corner than usually seen with normal grade rails
December 2017

10. Premium grade rail and RCF
STE-PR V/T SIC seminar
Premium grade rail and RCF
Premium grade rails have increased RCF resistance compared with ‘normal’ grade materials…
…but they will not always be the solution- they could introduce new problems
Premium rail will reduce RCF
RCF will be a problem on premium rail (none with 260 grade rail)
Premium rail will eliminate RCF
Premium rail will initiate RCF faster than 260
December 2017

11. How to develop guidance/understanding?
STE-PR V/T SIC seminar
How to develop guidance/understanding?
Benefits (or disbenefits) of different rail steels depend on
Curvature
Cant deficiency
Wheel/rail profiles
Vehicle PYS
Need to find a way to capture these in a set of guidelines without mandating complex modelling
(Track-Ex is mentioned a lot in the NR Asset Policy)
December 2017

12. STE-PR0033-00093 V/T SIC seminar
Track-Ex VDMs
For each cant deficiency, vehicle and wheel/rail combination…
December 2017

13. Example VDMs: PYS16MNm/rad, ‘new’ wheel/rail profile
STE-PR V/T SIC seminar
Example VDMs: PYS16MNm/rad, ‘new’ wheel/rail profile
December 2017

14. STE-PR0033-00093 V/T SIC seminar
RCF damage: 260 grade
December 2017

15. RCF damage: ‘Premium’ grade rail
STE-PR V/T SIC seminar
RCF damage: ‘Premium’ grade rail
December 2017

16. RCF damage: ‘Premium’-260 grade difference
STE-PR V/T SIC seminar
RCF damage: ‘Premium’-260 grade difference
Premium grade rail increases RCF
Premium grade rail reduces RCF
December 2017

17. Example results: Vehicle PYS16MNm/rad, new wheel/rail profile
STE-PR V/T SIC seminar
Example results: Vehicle PYS16MNm/rad, new wheel/rail profile
No RCF with premium grade
No RCF
Lower rate of RCF with premium grade
Reduced low rail RCF with premium grade
Higher rate of high rail RCF with HP
December 2017

18. STE-PR0033-00093 V/T SIC seminar
Example results: Vehicle PYS16MNm/rad, moderate worn wheel/rail profile
December 2017

19. Example results: Vehicle PYS16MNm/rad, heavy worn wheel/rail profile
STE-PR V/T SIC seminar
Example results: Vehicle PYS16MNm/rad, heavy worn wheel/rail profile
December 2017

20. Example results: Vehicle PYS16MNm/rad, all wheel/rail profiles
STE-PR V/T SIC seminar
Example results: Vehicle PYS16MNm/rad, all wheel/rail profiles
December 2017

21. Example guidelines: PYS16MNm/rad vehicle
STE-PR V/T SIC seminar
Example guidelines: PYS16MNm/rad vehicle
No RCF with premium grade
Hett Mill
Penarth
Shipley
No benefit for premium grade
Lower rate of RCF with premium grade
Reduced low rail RCF with premium grade
Higher rate of high rail RCF with HP
December 2017

22. Ongoing work Developing similar plots for other VDMs
STE-PR V/T SIC seminar
Ongoing work
Developing similar plots for other VDMs
Quasi-static- need to consider sensitivity to transient behaviour?
Extract a ‘simplified’ set of rules
But, installing on all curves shallower than 2500m radius is clearly not optimal
Of little benefit for most curves with cant deficiency
Significant disbenefit for tight radius curves with current rail steels
Need to give track engineers and designers confidence in where premium grade rails are best used
December 2017