  In the present design of the TESLA Linear Collider with integrated X-ray
Laser Facility it is necessary that 1 ms long bunch trains with about 10000
bunches are generated and distributed to several free electron laser (FEL) beam
lines. The different scientific applications of the X-ray FELs need specific
filling patterns of the bunches in the bunch train. It is shown that a fast
switch-yard based on a superconducting transverse mode cavity can be used to
generate the required bunch pattern in a flexible way while keeping the beam
loading in the main linear accelerator constant. The conceptual design of the
beam optics and the transverse mode cavity are presented.
