A pipeline processor having an exception program counter chain generates a return address in the exception program counter chain for an executing instruction. The vessel combines a high solids, plug flow path wherein low solids liquids are separated and directed to a high rate treatment path. For each sensor, contrast differences in the hFOV are used to identify a unique source of motion that is indicative of a remote object in the sensor hFOV. The output shaft is connected to the driven bevel gear such that it is prevented from rotation relative to the driven bevel gear but allowed to move axially. A retarding system is also provided, as is a terrain logging facility for logging the terrain of a route over which a vehicle travels.