unbraked

A "passenger/goods" cock is provided in each cab, by which, when placed in the "goods" position, the normal proportional brake application is slowed down. This is for use when hauling an unbraked or partially braked train, and prevents the unbraked stock from running into the locomotive or braked portion of the train with violence.

1958 September 28, “Swindon's First Main-Line Diesel Locomotive”, in Railway Magazine, page 603

The Modernisation Plan of 1955 forecast the brake-fitting of all goods wagons; but the majority of mineral wagons remain loose-coupled and unbraked and a four-axle locomotive of Type 3 or 4 power is, therefore, unsuitable for heavy mineral work - without a fitted "head" on the train - because of inadequate braking power.

1963 January, G. Freeman Allen, “Why B.R. are dropping high-power diesel-hydraulics”, in Modern Railways, page 25