The bug reporting system is the biggest bug so far...I've seen several sites listed but nothing official.
The train cart you mention needs fixed, as I have trouble too unless I go right thru the center of the opening. The graphics are ok, but I'm sure we'll see more polish in the final version. They probably 'dumbed it down' a bit so it would be a decent size download. I've noticed alot of bugs in the stats/awards system too. I've gotten medals for being the best player in a Deathmatch

, and several for kills from air support when I wasn't using it. I had to crank up the sensitivity as it felt slow and sluggish on default. There still seems to be something with movement that needs tweaked. Its not very tight when trying to stop and turn quickly.
All that said, I love the gold rush type matches. Makes players work together either on attack or defense. I play recon exclusively, but rarely sit in a spot on the hillside. I like getting into the action and defending crates, spotting targets, throwing sensors, etc. Try the QBU88 out, you won't be sorry.