Complex sentence: The current C Stock trains, six cars in length, replaced these trains from 1970 and one person operation of the trains was proposed in 1972, but due to conflict with the Trade Unions was not introduced until 1984.
Split into simpler sentences: The current C Stock trains, six cars in length, replaced these trains from 1970. One person operation of the trains was proposed in 1972, but due to conflict with the Trade Unions was not introduced until 1984.