Diagram of the 30 English stations and 2 Welsh stations served by Central Trains' backbone of licensed routes: Citylink.  At six stations its red, blue, yellow and green routes intersect, three of which (Peterborough, March and Ely) are uniquely where two routes overlap (yellow and blue).
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self-made, from information found on the <a rel="nofollow" class="external text" href="http://www.centraltrains.co.uk/templates/ctIndex.aspx?id=449">Citylink website</a>