Many hundreds of these arc roof carriages were built for MR and MSJS services over the period 1882 to 1895. Indeed, many were built by the G&SWR and the NBR as well as by the MR itself. As built they were oil lit but between 1892 and 1902 they were fitted with gas lighting, initially with fish tail burners and a single gas pipe. From 1908, gas mantles with pilot burners were introduced requiring a second roof-mounted gas pipe. Torpedo roof vents began to be fitted after 1906 (earlier over lavatories). All vehicles had the automatic vacuum brake with Westinghouse brakes also being fitted to the Scottish Joint stock. From 1901, carriages were fitted with internal alarm chains connected to the brakes via pipes and valve on one end of the carriage only. Some were hired and also transferred to the M&GN.