Bygone London transport (4)
I believe the answer is:
tram
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">bygone london transport</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tram that I've seen before include "Urban transport" , "Vehicle running on rails in road" , "It runs on rails" , "Road vehicle running on tracks" , "The Luas, say" .)