Complex sentence: In the past, all four steam locomotives and received overhauls at the Tweetsie Railroad in Blowing Rock, North Carolina, because they must be aside by the Federal Railroad Administration (FRA).
Split into simpler sentences: In the past, all four steam locomotives and received overhauls at the Tweetsie Railroad in Blowing Rock, North Carolina. Since these were steam locomotives, they must be aside by the Federal Railroad Administration (FRA).