TL;DR
Under the Baltic Sea between Denmark and Germany, crews are building the world's longest immersed tunnel: 18 kilometers (11 miles) of giant concrete sections cast on land, floated out and sunk into a trench in the seabed, carrying both a highway and a railway. Cars may still cross first, around 2032. The trains now look set to arrive about three years later than planned, in 2035 or after, according to a leaked memo from Denmark's state rail operator that RailFreight relayed on Oct. 30; this is a secondary report, and no new official schedule has been published. The main holdup is a 1960s bridge on the German side that has to be replaced with a tunnel of its own. For our full odds on when cars and trains roll through, and the timeline of milestones that gets them there, subscribe.
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