The final common design of steel open ballast wagon was introduced in 1907 and rated at 20tons. Later designs were 21 ft. 6in. over headstocks with 12ft wheelbase. Built up to nationalisation their code name TUNNY was sometimes carried, including being mis-spelt as TUNNEY, even on official BR documents.
DW80501 ZBO LING @ Ebbw Junction 80-09-09 � Paul Bartlett w