The National Capital Trackers, and other modular clubs, cannot use star wiring due to the nature of show setup and operations. We use bus wiring. The layout configuration changes with each show so the total length of the bus cannot be controlled. We do not dictate the type of track and the number of track joints per module (and bridge tracks between modules cannot be soldered). We went through several iterations of DCS signal improvement schemes - blocks, filters, bulbs, magic incantations, cursing the DCS demons, etc. What finally worked was demanding the bus wiring be standardized with 12g pairs (hot and ground) for each main line. No common ground except tying all the grounds together at the TIU. Each main line is fully isolated from other tracks. Crossing tracks between main lines have the ground rails fully isolated. Yards and sidings are fully isolated. No accessories draw main line power. Legacy signal is fed with a single wire to the common ground.
Our approach works for big layouts (i.e., the 120 ft. long York layout).
If you have an around-the-room layout, DCS will work fine on bus wiring - but keep each track's power bus (that carries the DCS signal) separate from all the other powered devices.
