Route abroad - a French line including terminals in London and France? (10)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Anagram of (abroad) ROUTE + ([ UN {one of the French forms of ‘a’} + L {line}] containing [including] N and E [ last letters of {terminals of} each of LONDO N and FRANC E ]) – &Lit clue