Complex sentence: Lord Farrar reorganised, at least, the expresses but by 1905 the whole system was so overloaded that no one able to predict when many of the trains would reach their destinations and there were crews spending as much as a whole shift standing at a signal.
Split into simpler sentences: Lord Farrar reorganised the expresses, but by 1905 the whole system was so overloaded that no one was able to predict when many of the trains would reach their destinations. Crews were spending as much as a whole shift standing at a signal.