Purchased as two four-wheel carriages in 1873 from the Metropolitan Carriage & Wagon Co., Ltd., of Saltley Works in Birmingham and later allocated fleet numbers B.7 and B.8, by 1882 these two carriages had become close coupled and were later mnounted on a new steel underframe, again supplied by the Metropolitan Carriage & Wagon Co., Ltd., in 1925 to become F.50.  The carriage in this form survived in service but the carriage bodies were scrapped and the frames retained as a runner.