Complex sentence: Courier Nurses were replaced by Passenger Service Reps in later years, but a high standard of service was maintained right up to May 1,1971 when Amtrak took over and dropped the "City of Miami".
Split into simpler sentences: Courier Nurses were replaced by Passenger Service Reps in later years. A high standard of service was maintained right up to May 1,1971 when Amtrak took over and dropped the "City of Miami".