The PPP contracts span a wide range of complex activities that are undertaken by Infraco and LUL on the Underground network. The contract sets down the information to be provided to LUL that LUL requires to fulfil its functions, for example to assure itself of the safety of the railway. In some areas, the contractual information sharing provisions are expressed in general terms and do not specify the form and content of submittals. It should be noted that the PPP contracts specifically refer to the Infracos undertaking their obligations on an open book basis. Some of these information requirements are set out below: