I can give a partial answer. We can perhaps provide some more data if required.
Each railway is required to have an emergency response assistance plan. They share aggregate numbers upon request with the communities through which they go. It's my understanding that first responders can have immediate access to whatever is being carried on a particular train involved in a particular occurrence.
Transport Canada may be in a better position to provide details, or the railway companies that I believe are going to be meeting with you in a couple of weeks.