motive power

plural motive powers

1. figurativelysometimesuncountableusuallyThe power that enables something to move.

   Using electricity as motive power for railroads will do away with fuel trains, tenders, coal handling, water, and all that.

   Synonyms: locomotion, motivity

2. collectiveuncountableusuallyrail transportThe locomotives or other powered units that operate on a railway.

   2 more examples

   While at first in the U.S.A. it may have been a matter of high-pressure salesmanship—and it has undoubtely been the irresistible enterprise of the General Motors Corporation, through its Electro-Motive subsidiary, that has set in motion this amazingly rapid transformation of American railway motive power, and has caused all the steam locomotive builders in the U.S.A. to follow suit or be left out in the cold—it seems now beyond dispute that, so far as the U.S.A. is concerned, the economics of the power question can be solved no other way.

   1950 January, Cecil J. Allen, “British Locomotive Practice and Performance”, in Railway Magazine, pages 12–13

   In the United States, where the railways are 90 per cent. dieselised today, diesel-electric power is the unvarying rule for independent locomotive units, and the only motive power exceptions are the highly successful 600-h.p. diesel-hydraulic railcars of the Budd "RDC" type, of which between 300 and 400 are now at work.

   1958 April 28, Cecil J. Allen, “British Locomotive Practice and Performance”, in Railway Magazine, page 268