Amtrak just expanded wi-fi service to new routes, so I was excited about Skrittering on long train rides... but on the NE Regional train I couldn't get Skritter to load the study page. It took me the better part of 2 hours and a lot of troubleshooting/reinstalling Adobe Flash before I realized that Amtrak apparently blocks some of the Google domains (e.g., you can't download Chrome by the usual method). Part of their bandwidth restriction efforts, I guess. If you VPN it works but if you don't have VPN, don't pull out your hair wondering what's wrong with Flash! Hope that helps some of you.

Try the www.skritter.cn domain if you're getting blocks like that. I think that might get around that Amtrak block, though it was made for accessing Skritter from mainland China.