Stabilization of Rail Track, CN Dundas Sub, Dundas to Copetown, Ontario

ABSTRACT: The paper summarizes the design of stabilization measures which were constructed in the portion of the Dundas Sub which lies between the towns of Dundas and Copetown, Ontario. Construction of the initial single rail track on the Sub took place in the early 1850’s; the track was twinned in the 1890’s. The affected section of track rises up from the base to the top of Hamilton Mountain (Niagara escarpment). It features a series of cuts, side slope fills, and embankments. Railway construction was carried out without the benefit of sophisticated construction equipment; construction fills were not subject to dense compaction. Cuts were made into hillsides to construct a level platform to support the track with fill being placed on the downhill side to add platform width. Design of the various sections of earth work associated with track construction was based on experience rather than analytical design methods. Over the past few decades, some sections of rail track which are supported by fill soils and track lying above native slopes on the downhill side, have experienced downhill movements as a results of much increased axles loads and much increased length of trains compared to the initial train loads. The paper reviews the design of stabilization measures at five sections of track. These stabilization designs have featured: a conventional gravity berm; a gravity berm featuring geosynthetic reinforcement to provide an oversteepened slope face; tie backs which are anchored into bedrock; soil nails to stabilize the slope height from rail track down to base of slope; and soil anchors to support the outer rail track at the top of a high slope. The rationale for design method selection is discussed for each site in conjunction with site constraints such as urgency, property limits, ensuring minimal effect on rail operations, site access restrictions, and cost.