Part of it had to be closed to traffic recently after a lingering thunderstorm damaged its northbound lanes and protecting it from corrosion and rust is a never ending battle.
Some definitions put that at 155 but there's a type of rail under development that could run at several times that speed and change transportation as we know it.
It's eleven stories high, and stretches 330 meters along the King's Cross railway tracks – that's longer than London's tallest building, the Shard, is high, by the way.
Even if some cities benefit, other places beyond the rail network may suffer: speed is attained partly at the cost of stops, so areas well served by existing services may find new lines bypass them.