Complex sentence: Passenger service continued despite several setbacks until 1937, when the ferry service was discontinued; without the ferry traffic, the line could not survive, and the last passenger trains operated on September 12 of that year, and the last mail trains on September 30.
Split into simpler sentences: Passenger service continued despite several setbacks until 1937, when the ferry service was discontinued; without the ferry traffic, the line could not survive. The last passenger trains operated on September 12 of that year, and the last mail trains on September 30.