Serving to illustrate Old English representative on the Italian railway (9)
I believe the answer is:
exemplary
'serving to illustrate old' is the definition.
I can't tell whether this defines the answer.
'english representative on the italian railway' is the wordplay.
'english' becomes 'exe' (I can't explain this - if you can you should believe this answer much more).
'representative' becomes 'mp' (Member of Parliament, a representative).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'the italian' becomes 'la' ('the' in Italian).
'railway' becomes 'ry' (abbreviation).
'exe'+'mp'+'la'+'ry'='EXEMPLARY'
Can you help me to learn more?
(Other definitions for exemplary that I've seen before include "Worthy of imitation" , "Worth following as an example" , "Perfect" , "warning" , "Ideal" .)