I work for a company that sub-contracts to Network Rail, the PC as asked us to do a work package plan for the client, when we install a bridge we are manufacturing in our workshops. Is it the PC who should be carrying out a work package plan or is it my company? Surley we are not working for the client, but the Princible Contractor. Can anyone clear this up for me please.

On the face of it, seems a reasonable request. It is surely a principle of CDM that specific areas of expertise are left for those with competencies and experience to deal with them appropriately?

The PC is may not have the necessary expertise for certain areas your work, therefore will require as much detail as possible for them to undertake their of planning, co-ordinating, and managing the H&S aspects construction phase. As a contractor your are required to provide them with the information that they require to do this i.e co-operate and provide the necessay information that might affect the H&S of any person undertaking the work or who maybe affected by it. In my experience of rail works PC's are not skilled in every element of a contractors work package (e.g signalling installation) they may have personnel available that able to advise them but it is not unusual that the contractor prepares their own WPP and provide it to the PC. It also allows for clear communication between PC and contractor and proper planning particularly possession and protection arrangements that may be required for the work.