helper grade

English

Noun

helper grade (plural helper grades)

1. (rail transport, US) A railroad gradient where helper locomotives are required to assist the train locomotives.
   • 1960 November, David Morgan, “"Piggyback"—U.S. success story”, in Trains Illustrated, page 684:

     On February 5-6, 1960, this westbound train made its run in 25 hr. 40 min. despite falling temperatures, fog, rain, sleet and snow; a 1 in 54 helper grade to the summit of the Alleghenies; and a load of 55 cars carrying 100 trailers for a gross tonnage of 3,856 tons.

References

• TheFreeDictionary