Am I alone in wondering why the hell they did not carry out these works on the weekends in March when there were no trains running? Instead, they are doing it between 1am and 9am tonight/tomorrow morning as it needs to be done when there are no trains...
You may be confused between the line closed to passengers and the line closed to trains. During engineering weekends it is quite common to see trains maintaining the track or carrying stuff to the work sites. I'm guessing these bridge works preclude all rail traffic.