Complex sentence: Their construction was complicated by the need to keep the railway bridge operating without interruptions, the Bakerloo Line tunnels passing only a few feet under the river bed, as well as the potential danger of unexploded World War II bombs in the Thames mud.
Split into simpler sentences: Their construction was complicated by the need to keep the railway bridge operating without interruptions. There was also the problem of the Bakerloo Line tunnels passing only a few feet under the river bed as well as the potential danger of unexploded World War II bombs in the Thames mud.