I'm currently trying to decide between 9/9 w/ Trains 10, and 8/8 w/ Trains 10.
I'd actually be interested to see 7/7 or even 6/6 vs two Train-10 Train Masters. I don't think it'd be winnable unless you went with some turbo-hyper-cheese for a quick win.
It does depend on the map, though. Starting from the corner of a crosshatch or the end of a snake is a lot different than starting from the middle of an X.
On the other hand, if you play vs two Train-10 Train Masters, even on 1/1 from a position that no trains will
ever path through your planets, that first cargo-spawned HK mkI is still going to kill you. Whether it happens within the first hour depends a lot of the map type (average distance between stations), random rolls in deciding how many cargo trains are included in the first few groups, and random rolls in deciding which stations to go to. But eventually those HkIs are gonna start coming out, and it's all aboard the pain train.