ruling gradient

plural ruling gradients

1. rail transportThe steepest uphill gradient in one direction on a section of railway line.

   For the next mile, the line falls, and then rises again, at a gradient of 1 in 50, the ruling gradient of the line.

   1950 December, R. C. J. Day and R. K. Kirkland, “The Kelvedon & Tollesbury Light Railway”, in Railway Magazine, page 839

   2 more examples

   In the next 65 miles the train climbs 2,470ft to the Arizona Divide on a ruling gradient of 1 in 70 and in steam days a fleet of helper engines was kept busy assisting the heavy trains over this section.

   1961 July, J. Geoffrey Todd, “Impressions of railroading in the United States: Part Two”, in Trains Illustrated, page 425

   Minor changes to control gear include the provision of automatic wheelslip protection, since these units will be operated on lines with ruling gradients of 1 in 60 or 1 in 80.

   1962 December, “The Oxted Line diesel-electric multiple-units”, in Modern Railways, page 385

   Synonyms: ruling grade