  In this article, a feasible switchyard design is proposed for the Shanghai
soft x-ray free electron laser facility. In the proposed scheme, a switchyard
is used to transport the electron beam to different undulator lines.
Three-dimensional start-to-end simulations have been carried out to research
the beam dynamic during transportation. The results show that the emittance of
the electron beam increases less than 10%, at meanwhile, the peak current, the
energy spread and the bunch length are not spoiled as the beam passes through
the switchyard. The microbunching instability of the beam and the jitter of the
linear accelerator (linac) are analyzed as well.
