Board Thread:Questions and Answers/@comment-771828-20140803111839/@comment-67.109.227.190-20170608213749

Medal of Achievement in Cornelius's contracts gives you a 100 return ... that is the highest of anything I have found on Trainstation. Just send all your spare gold trains to Cornelius and you can gain 5,800,000 XP's each time you purchase one. You can resell it for over 100,000,000.