Talk:Happy Birthday Achievements/@comment-203.43.41.170-20150814141527/@comment-1612180-20150819231002

You can only collect 100 XP during each train ride. Granted that's more than enough to satisfy this requirement of 80XP, but on some other achievements and tasks you might need to get more XP. So don't send your trains out for a week, otherwise you'll only be able to collect twice during that week (on the way out and on the way back in to your station).

And don't click the 6 or 10 minute trips either. You won't have enough time to collect all the XP from all your trains because it takes about 2.5 minutes to collect all 100 XP from each train. And that's not factoring in if you miss one and have to start counting all over again, that makes it take even longer.