@Francis,
From the BBC website:
"All rail services on the West Coast Mainline between Rugby and Stafford remained suspended.
A Network Rail spokesman said engineers had been unable to get onto the site because of the investigation, but were hoping to start work on Saturday afternoon.
"It's probably about a day's work and we hope to finish by Sunday evening. It should be clear for Monday morning commuters," he said."
So the engineers couldn't get on with the repairs until the crash investigators cleared off the site.
That to me seems a disproportionate state of affairs in the circumstances.