 These later conversions (and probably the earlier ones as well) included a shunter's cock being added similar to Tait G cars, to aid shunting Units (M-T-BT-) onto Blocks (M-T-T-M).This resulted in 7-car dogbox trains being formed as M-T-BT+M-T-T-M, releasing the G carriages for other services.The first two withdrawals of T swingdoor cars were in 1953 and 1956, with 46T and 86T respectively.