Guidance for rail grade selection STE-PR0033-00093 V/T SIC seminar Guidance for rail grade selection Mark Burstow Principal Vehicle Track Dynamics Engineer December 2017 December 2017

Background Part of V/T SIC’s strategic objectives: STE-PR0033-00093 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

Existing guidance NR/L2/TRK/2102 Section 9: specification of rails STE-PR0033-00093 V/T SIC seminar Existing guidance NR/L2/TRK/2102 Section 9: specification of rails Not clear where they should be used December 2017

Existing guidance TWI From 2005! STE-PR0033-00093 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

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

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

250m radius curve example, ‘normal’ grade rail STE-PR0033-00093 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

Comparison of premium and normal grade rail (9 months in service) STE-PR0033-00093 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

High rail condition: a surprising effect STE-PR0033-00093 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

Premium grade rail and RCF STE-PR0033-00093 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

How to develop guidance/understanding? STE-PR0033-00093 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

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

Example VDMs: PYS16MNm/rad, ‘new’ wheel/rail profile STE-PR0033-00093 V/T SIC seminar Example VDMs: PYS16MNm/rad, ‘new’ wheel/rail profile December 2017

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

RCF damage: ‘Premium’ grade rail STE-PR0033-00093 V/T SIC seminar RCF damage: ‘Premium’ grade rail December 2017

RCF damage: ‘Premium’-260 grade difference STE-PR0033-00093 V/T SIC seminar RCF damage: ‘Premium’-260 grade difference Premium grade rail increases RCF Premium grade rail reduces RCF December 2017

Example results: Vehicle PYS16MNm/rad, new wheel/rail profile STE-PR0033-00093 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

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

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

Example results: Vehicle PYS16MNm/rad, all wheel/rail profiles STE-PR0033-00093 V/T SIC seminar Example results: Vehicle PYS16MNm/rad, all wheel/rail profiles December 2017

Example guidelines: PYS16MNm/rad vehicle STE-PR0033-00093 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

Ongoing work Developing similar plots for other VDMs STE-PR0033-00093 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