Travelling by train, running to catch the one ten out (9)
I believe the answer is:
itinerant
'travelling' is the definition.
(I've seen this before)
'train running to catch the one ten out' is the wordplay.
'running' is an anagram indicator.
'to catch' indicates putting letters inside.
'the one ten out' becomes 'tine' (I can't justify this - if you can you should give a lot more credence to this answer).
'train' anagrammed gives 'irant'.
'irant' enclosing 'tine' is 'ITINERANT'.
'by' is the link.
Can you help me to learn more?
(Other definitions for itinerant that I've seen before include "Tie-in rant to a traveller" , "Travelling around" , "(Person) on the move" , "Moving from place to place" , "Wandering from place to place" .)