Rail Freight Task Force - Final Report (7737 kb) - City of Mitcham

7. OPTIONS FOR EXISTING RAIL CORRIDOR7.1 The Hills corridor was surveyed in the late 1870's after considerable discussion and seeking themost feasible route though the Mount Lofty ranges from the Adelaide Plain. Early alternative plansincluded taking the line via ‘The Gap’ where Truro now sits, tunnelling though the ranges, or goingsouth over the lower southern ranges.7.2 The needs for a railway line are simple and basically unchanged. Grades not exceeding about 2-3% (or 2 -3 metres rise in 100 metres) allow for steel wheels gripping steel rails most of the timewithout slip.7.3 Similarly curves were considered sharp if they were less than 40 metres radius, provided wagonswere 14 metres or less in length. Today’s wagons can be 29 metres long for which the absoluteminimum curve radii should be 90 metres. These minimum radii presuppose very slow trainspeeds.7.4 The Hills line has grades around 2% and curves as sharp as 190 metres with posted speeds of50km/h. Between Adelaide and Murray Bridge there are about 30 curves with radii around 200metres and posted speeds of 50km/h. In fact over this distance there are a total of 200 curves,making this one of the most curvilinear tracks in the world (See Fig. 7.1).7.5 In addition, there are 19 bridges under or over the railway line, along with 7 tunnels of almost2.5km of total length. The construction efforts in the 1880's must have been enormous.All of this costly construction effort produced just 96km of railway.Adelaide O’Bahn, circa 1984 – Courtesy R HuntPage 26