  W-pair production in e+ e- annihilation at 500 GeV is studied using different
Monte Carlo generators and the proposed detector for the Linear Collider in its
TESLA version. Semileptonic W decays are used to give hints for the detector
optimization and to determine the expected accuracy of the W mass determination
and the measurement of the anomalous triple gauge boson couplings. With an
expected luminosity of 50 inverse fb a W mass measurement with an accuracy of
15 MeV should be possible. The triple gauge boson couplings can be determined
with an accuracy in the order of ten to minus three.
