ruling gradient

English

Noun

ruling gradient (plural ruling gradients)

1. (rail transport) The steepest uphill gradient in one direction on a section of railway line, which determines the load that can be pulled by one locomotive over that section, according to the power rating of the locomotive. A typical ruling gradient could be 1:50 (2%). The ruling gradient can differ in the other direction on the same section.
   • 1950 December, R. C. J. Day and R. K. Kirkland, “The Kelvedon & Tollesbury Light Railway”, in Railway Magazine, page 839:

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

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

     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.

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

     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.

Synonyms

• ruling grade