i have followed this tutorial and it worked for me. It takes alot to make it look "realistic" and find a new way to do this if your are a perfectionist because you will never get it perfect with this setup because of the lattice. The lattice will stretch or shrink your geometry which I found unsuitable to me except for cartoon tracks or something quick. However, for your issue, make sure before you duplicate to delete history and group. select the group > duplicate and then everything should translate the same.