This is the Newark Flat Crossing: the only part left on the English rail network where two railway lines cross at grade like this.

The problem is, the East Coast Main Line - the north-south line in the image, one of the network's primary arteries - is crossed by another busy line. This puts a hard cap on rail traffic that can traverse the ECML. Complicating factors are the presence of the nearby River Trent, and the important A46 road, both of which also use bridges to cross the Trent nearby.

It's a mess: how would you re-engineer the crossing to remove the bottleneck and free up the ECML?