1. Ballast Migration – Progress 7 March 2013 Presentation by Louis Le Pen Researchers: Louis Le Pen and Geoff Watson

2. Summary of 10 th January meeting First site monitored Initial results Summary Ballast migration at Weedon November 2006 Presentation overview

3. Meeting 10 th January Present: Gareth Evans (Senior Technology Engineer (Rail)) – project champion, Paul Parcell (WCML), Kevin Thurlow (WCML), Louis Le Pen (UoS), Geoff Watson (UoS) Key points: Where this is known to occur Paul applies a tamp twice policy “has helped” Stoneblowing is also used at locations of rapid deterioration (e.g. Hodge Lane) On straight sections of track voiding can occur without migration Paul’s view is that the subgrade is the cause Could use GPR data to evaluate further (8 week surveys) During the speed upgrade “this was a major problem”

4. To London Site one: Hodge lane access near tamworth WCML 4 tracks, inner tracks are fast outer tracks are freight

5. Site one: Hodge lane access near tamworth WCML LEC2 108m to 109m, fast trains to London (second track in photo) Stoneblown Dec 2012 because “deteriorating fast” For January 2013 monitoring no visual evidence of migration

6. Site one: geophone arrangement

7. Site one: Weld

8. 1 3 46789 High sleeper end Site one: Geophone Arrangement 25 Vertical Horizontal 11 10 Weld Migration feature

9. How geophone data is interpreted Dominant axle and bogie frequencies can be obtained Geophone produces a voltage proportional to velocity of the sensor Knowing the response characteristics of the geophone the velocity can be computed Integration of data leads to calculated displacement Note that we generally ignore the first and last axle movements in the displacement trace (start up transients)

10. Pendolino, next to feature Estimate of at rest sleeper position Unusually high movement on inside of bend (V11) – possibly poor support conditions Range of movement 1346789 25 1110

11. Pendolino, At feature Some erratic movements, particularly for V6 and V5 which are the two geophones after the weld and the nearest to it 1346789 25 1110

12. Pendolino, After feature 1346789 25 1110

13. Some variation in deflections but this is not uncommon and has been seen on other sites we have monitored (0.6 mm to 2 mm) Pendolino, sleeper movements below Axle 15

14. Summary The Hodge Lane site shows some unusual features and it is possible that the nearby rail weld contributes to unusually complicated behaviour. However, at previous sites investigated (Weedon 2006) no rail welds were present within the migration features, so it would seem that migration cannot solely be associated with nearby rail welds. Further sites are needed for monitoring, ideally these would include sites where migration occurs but welds are not nearby Further monitoring at Hodge Lane planned More sites needed

15. Thank-you and any questions?

16. Geophone references: Monitoring the dynamic displacements of railway track. D Bowness, W Powrie, A C Lock, J A Priest and D J Richards. Proceedings of the Institution of Mechanical Engineers Part F, Journal of Rail and Rapid Transit 221 (F1), 13-22, March 2007. ISSN 0954 4097. doi: 10.1243/0954409JRRT51. Awarded the IMechE John F Alcock Memorial Prize and the IMechE Thomas Hawksley Medal, 2008 Determination of dynamic track modulus from measurement of track velocity during train passage. J A Priest and W Powrie. American Society of Civil Engineers Journal of Geotechnical and Geoenvironmental Engineering 135(11), 1732-1740, November 2009, ISSN 1090-0241. doi: 10.1061/_ASCE_GT.1943-5606.0000130

17. Review of cost Effective start date meeting of 10 th January One site monitored, installation on overnight possession, removal 2 days later on blockage Two staff members time contributions so far: approximately 4 days for the monitoring. 2 days for meeting in Milton Keynes 1 day for preliminary data assessment Estimate of total so far: £4000