The risk models provided at this web site were created by Network Rail, Railway Safety and London Underground Limited to provide them with insight into the sources of risk on the relevant railways. We hope that they can be of wider value but we do need to provide some cautionary notes.

All risk models are approximate and limited in applicability. The models provided here are no exceptions.

Assessing risk requires specialist knowledge to produce useful results. If you use the risk models here to help you assess risk then we assume that you have that knowledge. We cannot tell you everything you need to know to use these models properly, but we do list some of the main points you should consider if you are:

• drawing up a specification for a railway change.
• implementing a railway change.
• reviewing a railway change or safety submission.

Some more detailed practical guidance is provided in the Application Guide.

One of the benefits that the authors of the models hope to obtain from sharing their work with you is to receive constructive comment that they can use to improve the models. We hope that you will use the models in that spirit and warmly welcome any comments. You can contact us here to submit comments and we will pass them on to the authors.

Please note that we do not guarantee that the versions of the models presented on this web site are the most recent versions. If it is important to your application to use the most recent version you should check directly with the authors.

• If you are performing risk assessment in drawing up the specification then all the points in the 'implementing a change' list below will be applicable to you.
• If you are drawing up a statement of work which includes risk assessment, make sure that this statement leaves the contractor with the flexibility to follow the points below and be careful not to encourage them to depart from them. In particular, consider very carefully how applicable any risk model is before requiring the contractor to use it.

Points to consider if you are implementing a railway change

• The models make assumptions about the railway, some explicit and some implicit. You will need to identify these assumptions and find out how many still hold in your application in order to decide whether a model is applicable at all.
• Even if the model is applicable, it is likely that your application will still be different from the situation assumed so you will need to adjust the model accordingly before using it.
• You should consider carefully how much reliance you should place on any predictions derived from the model data. In general you should corroborate the predictions with further analysis or data that is specific to your application.
• Any model can only inform careful thought, not replace it. Using models can never be enough on its own to help you discharge your legal duty of care.

Points to consider if you are reviewing a safety submission for a railway change

• If the submitters have used a risk model, have they analysed the differences between the situation assumed by the authors of that model and the submitters' application?
• Is the risk model applicable?
• Have the submitters made all the necessary adjustments?
• Are the submitters placing unjustified reliance on the risk model data?
• Have the submitters corroborated the risk model data?
• Have the submitters carefully thought through their specific application?
• Have the submitters fully discharged their legal duty of care?