If you're asking if you can open a .im in Gmax, the answer is no. The only person who can access that is the original creator.
To open someone elses content without their consent is illegal.
If you are new to content creation, then that is a very important thing to know. When you make something, it will be saved as a .im file. Keep the Gmax file backed up somewhere so you can access it again if need be.
Ok thx for answer. I have a one last question... Where I can find tutorial for tracks or turnouts? I wanna try to make one but I don't know how :? I made a lot of buildings and now I want try make a 3d tracks and turnouts...