Repair method for underground railway track - involves casting concrete columns in bored ballast which support rails

摘要

The method is for repairing an underground railway without removing the ballast, by drilling through the ballast (1) and into the foundation (2) below. Vertical metallic rods (5), the upper ends of which are threaded, are placed into the cavities (3) and secured into the foundation (2) using quick-setting resin. Concrete is then cast into the ballast to form columns (4), adjacent pairs of which are interconnected by bridging plates (10) supporting the rails (20) on spacers (11). Certain bridging plates extend towards the interior of the track and carry insulators which support the electricity supply rail.