15.Countermeasure work on ballasted Shinkansen track to prevent ballast migration

  • Ballast migration on a ballasted Shinkansen track was reproduced by vibration machine, producing insight into the mechanisms leading to this phenomenon.
  • A countermeasure was developed using biodegradable aqueous polymer solution to stabilize the ballast on the track.
  • This measure manages to reduce costs by 50%, and allows tamping work to be conducted after the procedure.

On ballasted Shinkansen track, in curves with large cant the surface ballast flows from the outer rail towards the inner rail due to the passage of trains, which can cause “ballast migration”, and lead to a frequent need for maintenance work.
As a measure to counteract this phenomenom, a vibration machine was employed with controllable load direction, to conduct repetitive tests taking into account the excessive centrifugal force which occurs when a train runs through a curve (Fig. 1). The results of these tests showed that it was possible to reproduce ballast migration through tests conducted inside (Fig. 2).
Results from investigations into the mechanisms producing ballast migration revealed that dynamic displacement of the sleepers was causing the ballast to shake, and that using rectangular section sleepers and track bed improvement were effective. An additional low-cost countermeasure involved using a biodegradable aqueous polymer solution to stabilise the surface of the ballast (Fig.3 and 4). This method is approximately 50% more economical than frequent ballast scraping work, and allows tamping once work has been completed.

Fig 1 Loading tests taking into account excessive centrifugal forces
Fig 2 tests to reproduce ballast migration
Fig 3 Stabilization of ballast using polymer solution
Fig 4 Confirmation of effectiveness of ballast migration countermeasure