A bulk material conveyor belt system comprises a belt, a track mounted device, and a support device. The track mounted device comprises a first track. The support device comprises a second track and a locking device. The second track is engage with the first track in a manner such that the support device limits relative movement between the track mounted device and the belt while the support device also allows the track mounted device to slide relative to the support device along a path defined by the first and second tracks. The locking device comprises a movable portion that is movably attached to the second track and that can selectively bias the first track in a direction other than along the path in a manner creating sufficient friction between the first and second tracks that renders the first and second tracks immovable relative to each.