The drop in Jarvis' share price is yet another example of the rough ride Britain's railway contractors are being given. Let's get thing straight: of course they want safe railways, not least because safe railways are good business – the consequences of accidents are terrible and the penalties are severe. But accidents do happen. It is an endless task to upgrade a railway built mainly between 1840 and 1860 and suffering from decades of underinvestment.

Just for a minute, forget the victims and the outcry against contractors, and let me answer the accusations.

  • "Railway privatisation has confused safety with profit and responsibility issues."

    The new maintenance contracts focus on safety and include penalties for poor track performance: fail to perform and risk losing the business.

  • "Unsafe railways have thwarted the resurgence of public transport and contributed to road traffic congestion."

    The railways have never been busier. There has been a massive increase in passenger and freight traffic and the safety record is improving. We kill 3400 people a year on the roads compared with fewer than 20 a year on the railways.

  • "British Rail technical staff have been replaced by a chain of subcontractors, with the result that work is being executed by untrained people recruited in pubs."

    This hurts. I am in contact with all the main rail contractors and their key staff. They have performed miracles in trying circumstances. The Potters Bar tragedy may turn out to be human error, but the contractors are desperately upset about any accident. They work long and often unsociable hours with a high level of professionalism. The criticism they are getting is shameful and demotivating.

  • "Potters Bar cannot be vandalism – it would require specialist knowledge and tools to carry this kind of act out."

    It could be sabotage. Many have a vested interest in the failure of privatisation and have the necessary specialist knowledge. This is a horrible thought, but is it so implausible? Have the doubting media actually asked whether similar acts have been identified in recent months, as my information says they have?

    We are dealing with an old railway that is being worked harder and harder and trackworkers who are similarly stretched. It is time to stop blaming the system and stop expecting a perfect safety record – it will never be achieved. Stop hammering the men, women and companies that are working hard to make a difference, and succeeding. Read the statistics and forget the spin.