Tries again facing front of Eurostar train (8)
I believe the answer is:
rehearse
'train' is the definition.
(eg actors rehearse to train for a show)
'tries again facing front of eurostar' is the wordplay.
'tries again' becomes 'rehears' ('hears' can be a synonym for 'tries' so perhaps 'rehears' is OK for 'tries again').
'facing' means one lot of letters go next to another.
'front of' says to take the initial letters.
The first letter of 'eurostar' is 'e'.
'rehears'+'e'='REHEARSE'
(Other definitions for rehearse that I've seen before include "Practice a play" , "Practise (one's lines)" , "Practise - run through" , "What actor does to prepare for play" , "Go over" .)