Actually, since I just remembered that I had this
webpage about friction saved I did something quick, pulling a train on the track is like 10x easier than pulling a vehicle with wheels too assuming the size is the same. At the speed A-Train was going this could be done by IRL Olympian depending on the train size. Pulling a small train (6000 US tons) is around
Peak Human [2433.2872 N or ~~ 248.13 kg], but that's like 100 kg below the current IRL records. Pulling a large train (18000 US tons) would take around
Class 1 [7299.86159 N ~~ 744.38 kg]. Even if he was
pulling the largest train in the world, at the speed he was moving its only
Class 5+ [44584.238 N ~~ 4546.33 kg].
He would have to be a train larger than the normal range to only slightly boost his tier lol.