RE:notice your trains, the wheel are not tight to the trackThat's the way they are designed to work. Railway axles have no differential. Both wheels turn at the same rotation. The running surface of the wheel is not flat, it is semi conical, with a larger circumference on the inside of each wheel. When they go around a turn, centrifugal force pushes the wheel towards the outside, thereby making the outside wheel travel the extra distance required on the outside rail by running on the bigger circumference while the inside rail runs on the smaller circumference. So while both wheels turn at the same rate, the outside wheel travels farther than the inside wheel in the same amount of time and rotation. The things we learn.