Simplify the following text for a Grade 8 native English-speaking person.
Original: Construction work began in 1962 on the Walthamstow â '' Victoria section and continued until 1972 , when Pimlico station was opened .
Simplified: The construction work on the Walthamstowâ `` Victoria section began in 1962 . It continued until 1972 , when Pimlico station was opened .