Complex sentence: It is often confused with this vehicular bridge to the north, officially called the Senator Ted Hickey Bridge therefore, it is commonly called the Seabrook Railroad Bridge, that now carries only trains across the canal.
Split into simpler sentences: It is often confused with the adjacent vehicular bridge to the north, the Senator Ted Hickey Bridge. Therefore, it is commonly called the Seabrook Railroad Bridge as it carries only trains across the canal.