What is the point of fining Network Rail?

Overhead Electrification Contractors 1, originally uploaded by jovike.

Network Rail has been fined £14 million because works carried out over the Christmas and New Year period at Liverpool Street Station, Glasgow and Rugby were not completed on time.

What is the point of fining a public sector company? It is taxpayers' and passengers' who will have to pay. It may be possible for NR to pass the fine on to its consultants, but I doubt if that will happen.

The reason for the over-run, apparently, is the shortage of qualified people to put up the overhead electric wiring, like those in the picture. If there was even a small rolling programme of electrification, there would have been more trained staff available, but it turned out that workers were being poached between sites by team leaders desperate to get the work completed.