A pig died on the train (6)
I believe the answer is:
aboard
'on the train' is the definition.
'a pig died' is the wordplay.
'pig' becomes 'boar' (male pig).
'died' becomes 'd' (abbreviation next to the year of someone's death).
'a'+'boar'+'d'='ABOARD'
(Other definitions for aboard that I've seen before include "A poet penning nothing on vessel" , "on a ferry?" , "On ship or plane - not on land" , "On a ship, train, plane or other vehicle" , "... [CRUISE SHIP] here, perhaps" .)