Complex sentence: In early 1994, near its western terminus, the train was rerouted onto the Santa Fe Third District via Fullerton and Riverside when previously it served Pasadena and Pomona via the Santa Fe Pasadena Line, until that route was closed to all through-traffic.
Split into simpler sentences: In early 1994, near its western terminus, the train was rerouted onto the Santa Fe Third District via Fullerton and Riverside. Previously it served Pasadena and Pomona via the Santa Fe Pasadena Line, until that route was closed to all through-traffic.