Complex sentence: On 12 September 1966 British Rail withdrew all passenger services to Leiston and beyond; however, the line to Leiston remains active, but only for the purpose of removing nuclear materials from Sizewell power station--which is expected to cease entirely by 2012.
Split into simpler sentences: On 12 September 1966 British Rail withdrew all passenger services to Leiston and beyond. However, the line to Leiston remains active, if only for the purpose of removing nuclear materials from Sizewell power station--which was expected to cease entirely by 2012.