The rails on a "proper" one are 30" long. The "roadbed" on a proper one is made up of one 30" length of plastic, consisting of three sections, each of which mimic a piece of 10" roadbed. This is especially clear when viewed from the bottom.
Going back to the rails: Do you have three separate 10" rail sections, mated with pins, to reach 30" in length? Or are the rails one continuous piece of rail 30" long?
Mike