Complex sentence: Coin operated public luggage lockers were commonplace in bus stations and rail stations in some countries from the 1950s to the 1970s when they were eliminated for concern that bombs may be hidden in them.
Split into simpler sentences: Coin operated public luggage lockers can be present in bus stations and rail stations. In some countries they were commonplace from the 1950s to the 1970s, but eliminated for concern that bombs may be hidden in them.