  Pulse-to-pulse orbit jitter, if not controlled, can drastically degrade the
luminosity in future linear colliders. The second goal of the ATF2 project at
the KEK accelerator test facility is to stabilise the vertical beam position
down to approximately 5% of the nominal rms vertical beam size at the virtual
Interaction Point (IP). This will require control of the orbit to better than 1
micrometre at the entrance of the ATF2 final focus system. In this report
simulation studies are presented for vertical jitter propagation through the
ATF2 extraction line and final focus system, and the jitter is evaluated at the
IP. For these studies pulse-to-pulse vertical jitter measurements using three
stripline beam position monitors are used as initial inputs. These studies are
performed for the case of a bunch-train with three bunches, but could easily be
extended for a larger number of bunches. The cases with and without intra-train
orbit feedback correction in the extraction line of ATF2 are compared.
