Thanks bignosemac, sounds a cogent reason.
Can't say it was very welcome for those of us on the train, having to get off at a freezing Reading station! There seemed to be a LOT of delayed trains that morning...
Seems to be a bad time for services which pass through Reading at the moment. I did notice the major disruption on Monday morning and thought I was lucky to escape it (although my journey on the Gatwick line suffered as a result of unrelated issues)