The members Hw=p2 +Vw(x) of ergodic families of random operators, defined in h=L2(Rd), are considered as acting in fibers in a direct integral decomposition of k=L2(W, P(dw);h), (W,P) being the underlying probability space. Such a formulation may turn out to be useful in providing a rigorous background for theoretical physical methods employed in treating random systems. As an example a rigorous definition of the mass operator S(z) is presented and the formulation of transport equations in a functional analytic setting is briefly indicated. In case there is translational invariance in the probability law the operator H is shown to be unitarily equivalent to an operator o(^,H), which can be decomposed, o(^,H) Æ o(^,H)(k), in a way that diagonalizes p. Thus problems about averaged time evolution can be formulated entirely in terms of o(^,H) (k) in L2(W, P).