  Given an irreducible contractible open 3-manifold W which is not homeomorphic
to R^3, there is an associated simplicial complex S(W), the complex of end
reductions of W. Whenever W covers a 3-manifold M one has that the fundamental
group of M is isomorphic to a subgroup of the group Aut(S(W)) of simplicial
automorphisms of W.
  In this paper we give a new method for constructing examples W with S(W)
isomorphic to a triangulation of R. It follows that any 3-manifold M covered by
W must have infinite cyclic fundamental group. We also give a complete isotopy
classification of the end reductions of W.
