Rach_TA_Filter only filters out the RACH beyond certain radius as defined by the value set. Hence MS beyond this radius can camp on this cell. (if this is the best server) but such mobile will not be able to access the network, their request will be filtered out by this parameter.
My concern is how a mobile in this condition be able to access the network resource? is their any parameter to push them away since they are on the cell they cannot use by setting of RACH_TA_Filter