What is the highest possible score in Ticket To Ride: Europe?
I had the same question, but having scored 189 in a game a couple of weeks ago, I couldn't believe 195 is the max score.
Edinburgh - Athína gets 21 points with 20 carriages, so I decided to explore possibilities from that route.
I set up the board and checked for the best routes to add.
I came up with this setup:
Points for the routes

Edinburgh - Athína ----------&gt; 21 points
Edinburgh - Paris ---------------&gt; 7 points
Paris - Zágráb ------------------&gt; 7 points
Paris - Wien ---------------------&gt; 8 points
London - Wien ----------------&gt; 10 points
London - Berlin -----------------&gt; 7 points
Berlin - Bucuresti --------------&gt; 8 points
Berlin - Moskva ---------------&gt; 12 points
Berlin - Roma -------------------&gt; 9 points
Roma - Smyrna ----------------&gt; 8 points
Zágráb - Brindisi ---------------&gt; 6 points
Zürich - Brindisi ----------------&gt; 6 points
Zürich - Budapest -------------&gt; 6 points
Amsterdam - Wilno ----------&gt; 12 points
Athína - Wilno ----------------&gt; 11 points
Essen - Kyïv ------------------&gt; 10 points
Venezia - Constantinople ---&gt; 10 points
Frankfurt - Smolensk --------&gt; 13 points

This makes a total of 150 for the shorter routes and 21 for the long one (=171)
European Express
Track length 43+2 (10 points for longest route/European Express)
Points for the carriages:

Edinburgh - London_____________________4 carriages_____7 points
London - Amsterdam____________________2 carriages_____2 points
Amsterdam - Essen_____________________3 carriages_____4 points
Essen - Berlin_________________________2 carriages_____2 points
Berlin - Wien__________________________3 carriages_____4 points
Wien - Budapest_______________________1 carriage______1 point
Budapest - Zágráb______________________2 carriages_____2 points
Zágráb - Venezia_______________________2 carriages_____2 points
Venezia - Zürich________________________2 carriages_____2 points
Venezia - Roma________________________2 carriages_____2 points
Roma - Brindisi________________________2 carriages_____2 points
Brindisi - Athína________________________4 carriages_____7 points
Athína - Smyrna_______________________2 carriages_____2 points
Smyrna - Constantinople________________2 carriages_____2 points
Constantinople - Bucuresti_______________3 carriages_____4 points
Bucuresti - Kyïv________________________4 carriages_____7 points
Kyïv - Smolensk________________________3 carriages_____4 points
Smolensk - Moskva_____________________2 carriages_____2 points

Points for the carriages is 58 in total (this score is not that high, so there might still be room for a few dozen points of improvement.)
Stations:

Wilno (from Kyïv or Smolensk)
Frankfurt (from Amsterdam, Essen or Berlin)
Paris (from Zürich or Frankfurt)

171+10+58=239 points.