1) Pair attached to an axle
Found on
https://www.crosswordclues.com/clue/wheelset
[rail transport] A wheelset is the wheel-axle assembly of a railroad car. The frame assembly beneath each end of a car, railcar or locomotive that holds the wheelsets is called the bogie (or truck in North America). Most North American freight cars have two bogies with two or three wheelsets, depending on the type of car; short freight cars...
Found on
http://en.wikipedia.org/wiki/Wheelset_(rail_transport)
No exact match found.
