A sample tube transport system that includes a track adapted to provide a path for one or more carriers between a plurality of modules. The system includes at least one upper conveyor system having an upper belt configured to wrap around a first upper pulley and a second upper pulley, and a plurality of upper magnets affixed to the upper belt to move the one or more carriers along the track adjacent the upper belt. The at least one lower conveyor system includes a lower belt spaced vertically below the upper belt and configured to wrap around the first lower pulley and the second lower pulley, and a plurality of lower magnets affixed to the lower belt. Each of the plurality of lower magnets are positioned to attract and move the one or more carriers along the track adjacent the lower belt.