A tube wagon, like B731708, is a long wheelbase wagon with steel ends and low wooden sides.  450 were built to this lot, with a total of 2350 built to this diagram.  It is on roller bearing axles and is 22 tons.  This wagon was withdrawn by British Rail in December 1988.

It was fitted with seats and was used to give rides on certain open days.  Over the last few years it has carried Santa's sleigh and reindeer for Christmas Steamings.  During 2002 it has been refurbished for "fourth class" passenger seating in the downyard.