Complex sentence: Rail travel was in decline across the UK in the 1960s and 1970s when the Beeching Axe was imposed and during the 1970s, two outer platforms used by terminating trains were abandoned and the third rail was removed.
Split into simpler sentences: Rail travel was in decline across the UK in the 1960s and 1970s when the Beeching Axe was imposed. During the 1970s, two outer platforms used by terminating trains were abandoned and the third rail was removed.