Complex sentence: The complete production run of 50 locomotives were build in just over a year, with D400 entering service in October 1967 and D449 in November 1968.
Split into simpler sentences: The complete production run of 50 locomotives were build in just over a year and numbered from D400 to D449. D400 entered service in October 1967 and deliveries were completed with D449 in November 1968.