  String-localized quantum fields transforming in Wigner's infinite-spin
representations were introduced by Mund, Schroer and Yngvason. We construct
these fields as limits of fields of finite mass $m\to 0$ and finite spin
$s\to\infty$. We determine a string-localized infinite-spin quantum
stress-energy tensor with a novel prescription that does not refer to a
classical Lagrangean.
