A substrate processing apparatus including a transport chamber having an end and defining more than one substantially linear substrate transport zone where each transport zone extends longitudinally along the transport chamber between opposing walls of the transport chamber and at least one of the more than one substantially linear substrate transport zones is configured as a supply zone for enabling transport of substrates from the end and at least one of the more than one substantially linear substrate transport zones is configured as a return zone for enabling transport of substrates to the end, and at least one substrate transport located in and movably mounted to the transport chamber for transporting substrates along the more than one substantially linear substrate transport zone, where each substrate transport zone is configured to allow the at least one substrate transport to move from one transport zone to another transport zone.