tractive

The outer third of the wing of a vulture consists of the wing tips. The inner two-thirds of the wing are cambered (when the wing is extended), and are concerned with lifting effort in unsoarable air and with lifting and tractive effort in soarable air.

1912, Flight

Engines with heavy snow ploughs are ordered to raise steam to a state of readiness, and freight trains may be cancelled or permissive loadings halved. This latter feature is of vital importance when it is borne in mind that trains are often snowed in through coming to rest between stations because of loss of tractive power.

1960 January 28, M. Harbottle, “Maintaining Services after Heavy Snowfalls”, in Railway Magazine, page 10