i just purchased an Alco 2-6-0 New York Central. It will not stay on the rail. I have had to remove the front wheels to keep it working properly. Now, there is a small spring which holds the wheels down, but I am thinking that this spring does not apply enough tension. I went over my entire layout, making sure every turn was correct, and all tracks match properly, but it will not run with the front 2 wheels!