Adhesion between wheel and rail discussion with Mr. M.W. Astle-Fletcher on 18th January, 1967 (IM-APT-020)

It is evident that the required figure of 15% or even 7.5% cannot be guaranteed under all conditions unless some form of [texts omitted as illegible] is employed. It is, therefore, recommended that immediate consideration be given to the initiation of experimental work on liquid or dry [texts omitted...