Nothing really but the MD spent a number of years looking at what has worked/failed in other attempts and worked over this period closely with MTM in Melbourne to fine tune the product and develop the optimal system, which he considers (obviously) superior to the only other comparable offering from JCDecaux. JCDecaux have rolled out a similar thing in HK in 2010 but from what I can tell, they have not rolled it out to many other places, whilst CBS's system was just bad and had that many problems they contended their contract (for all rail advertising not just cross track). APN bought lower quality systems that weren't wireless to do Sydney on their own but have effectively conceded to adverting duties with on XTD's behalf for Melbourne and Brisbane.
JCDecaux don't have much in the way of US rail advertising so aren't in a position to provide a counter solution to most rail operators, whilst none of the major US OOH media groups have a cross track solution. These screens are implemented under multi-year contracts so first in is best dressed and at this point it is only XTD in the running. A potential outcome is that if XTD win a bunch of US (or other) contracts, gets them up and running, that one of the majors will take a serious look at a takeover as entry into this niche.
XTD Price at posting:
21.5¢ Sentiment: Buy Disclosure: Held