Complex sentence: The former down bay platform fell into disuse in 1917 following closure of the line to Selsdon, reopened upon electrification in 1935 with through services to London.
Split into simpler sentences: The former down bay platform fell into disuse in 1917 following closure of the line to Selsdon. The line to Selsdon was reopened upon electrification in 1935 with through services to London.