A trolley for a rail, the trolley comprising: a frame; a set of wheels, including a first wheel and a second wheel, rotatably coupled to the frame; and an attachment member, coupled to the frame, for attachment, preferably suspension, of a load therefrom, in use; wherein the first wheel is rotatable in a first plane about a first axis and the second wheel is rotatable in a second plane about a second axis; wherein the first plane and the second plane define a line, wherein the line is the intersection of the first plane and the second plane; wherein the attachment member is arrangeable in: a first configuration, wherein the attachment member is arranged at a first angular displacement about the line; and a second configuration, wherein the attachment member is arranged at a second angular displacement about the line, wherein the first angular displacement and the second angular displacement are different; characterised in that: the trolley comprises a guide coupled to the frame, arranged to guide the attachment member between the first configuration and the second configuration; wherein the attachment member comprises a roller arranged to roll on the guide, wherein the roller is a grooved roller and/or wherein the guide has a circular-cross section. a frame; a set of wheels, including a first wheel and a second wheel, rotatably coupled to the frame; and an attachment member, coupled to the frame, for attachment, preferably suspension, of a load therefrom, in use; wherein the first wheel is rotatable in a first plane about a first axis and the second wheel is rotatable in a second plane about a second axis; wherein the first plane and the second plane define a line, wherein the line is the intersection of the first plane and the second plane; wherein the attachment member is arrangeable in: a first configuration, wherein the attachment member is arranged at a first angular displacement about the line; and a second configuration, wherein the attachment member is arranged at a second angular displacement about the line, wherein the first angular displacement and the second angular displacement are different; characterised in that: the trolley comprises a guide coupled to the frame, arranged to guide the attachment member between the first configuration and the second configuration; wherein the attachment member comprises a roller arranged to roll on the guide, wherein the roller is a grooved roller and/or wherein the guide has a circular-cross section. a first configuration, wherein the attachment member is arranged at a first angular displacement about the line; and a second configuration, wherein the attachment member is arranged at a second angular displacement about the line, wherein the first angular displacement and the second angular displacement are different; characterised in that: the trolley comprises a guide coupled to the frame, arranged to guide the attachment member between the first configuration and the second configuration; wherein the attachment member comprises a roller arranged to roll on the guide, wherein the roller is a grooved roller and/or wherein the guide has a circular-cross section. the trolley comprises a guide coupled to the frame, arranged to guide the attachment member between the first configuration and the second configuration; wherein the attachment member comprises a roller arranged to roll on the guide, wherein the roller is a grooved roller and/or wherein the guide has a circular-cross section.