Abstract: An arrangement for safe transition of a trolley between a first and a second suspended rail when they are in an end-to-end position with each other, and for safe operation of the trolley when the rails are in un-aligned positions relative each other. The arrangement comprises a liftable first stop member, a liftable second stop member and two pairs of engaging members. The liftable stop members are adapted to block the trolley from accidentally leaving the rails when the rails are in the un-aligned positions, and to unblock the rails when the rails are in the end-to-end position. The engaging members of the pairs of engaging members are arranged to engage with each other when the rails are in the end-to-end position to lift the stop members, thereby unblocking the rails in order to allow a transition between the rails.