Rio de Janeiro
I don't know what the latest rule set is, but I really enjoy the game the way I play it:
1) setup. Give each player 5 regular shares instead of 4.
2) use the official championship method to create the deck (with 4 main piles and 5 6-cards piles)
3) now this is the biggest change: use the Airlines Europe rules for UP shares. After drawing the track card players have now 3 alternate options: A. Build, B. Invest, C. Exchange. You cannot draw or exchange UP shares in option A anymore. If you want them, you must choose option C. and exchange either 1 share with 1 UP or 3 shares with 2 UP. IMPORTANT: the cards you give up for UP shares can come for your hand and/or from your stock. After the exchange, don't forget to discard a track card!
Those changes give UP the great balance of Airlines Euope but without its forgiveness.
Yea, I kinda thought a bit about doing that... The ONLY aspect that I prefer from UP that's not in Airlines Europe is that it's way less forgiving on the track building.