Passengers
I believe the answer is:
riders
'passengers' is the definition.
('rider' can be a synonym of 'passenger')
This is the entire clue.
(Other definitions for riders that I've seen before include "... To The Sea (J.M. Synge)" , "Synge play '. . . . . . to the Sea" , "Equestrians" , "Knights" , "qualifications" .)