  W_{1+infty} is defined as an infinite dimensional Lie algebra spanned by the
unit operator and the Laurent modes of a series of local quasiprimary chiral
fields V^l(z) of dimension l+1 (l=0,1,2,...). These fields are neutral with
respect to the u(1) current J(z)=V^0(z); as a result the (l+2)-fold commutator
of J with V^l vanishes. We outline a construction of rational conformal field
theories with stress energy tensor T(z)=V^1(z) whose chiral algebras include
all V^l's. It is pointed out that earlier work on local extensions of the u(1)
current algebra solves the problem of classifying all such theories for
Virasoro central charge c=1.
