Are U.S. players allowed to play in this?

Lert: So much nationalistic bullcrap in there ....   But, besides that, a few things you need to remember:   1) The test server is located in russia 2) The RU playerbase is several orders of magnitude larger than the NA playerbase 3) The test server is typically populated by inexperienced casuals who don't have anything bigger than a tier 5 unlocked and go "Wheee, look at all the tier 10 tanks I can drive for free without needing to grind them!" 4) The test server isn't there for you to have good battles. It's there for WG to get live test data on their changes / updates 6) Looking at the time of your posting, it's prime time for the RU server and the vast majority of NA players are still asleep   Points 1, 2 and 6 combined mean that, yes, there's going to be an overwhelming majority of RU players on the test server.   And as for your question posed in the thread title: Well - .... Duh. If NA players weren't allowed on the test server, why would they offer a download to it, make a separate subforum about it and make provisions for NA players to connect to it?