Abstract: Disclosed are a method and apparatus for producing a conduit system (10) for use on-board a vehicle (3). The method comprises: identifying a plurality of source apparatuses (4) located on-board the vehicle (3) and from which a resource is to be transferred via the conduit system (10); for each identified source apparatus (4), identifying one or more sink apparatuses (6) located on-board the vehicle (3) and to which that source apparatus (4) is to transfer, via the conduit system (10), a resource; using relative locations of the identified source and sink apparatuses, producing a digital model (62) for the conduit system (10) including specifying conduits (12-24) for coupling the source apparatuses (4) to the sink apparatuses (6) and arranging the conduits (12-24) such that each conduit (12-24) shares a common conduit wall with at one other conduit (12-24); and, using the digital model (62), producing the conduit system (10).