Sources of information for CM within systems engineering (transport?)

Hi everybody, this is my first post so I introduce myself quickly: I have just been hired as CM engineer in projects of mass transit signalling. I am new to all this world of CM and need to get into this asap but I only get info about software CM (almost nothing about systems engineering meaning CM for signalling projects in mass transit).

Could you please help me to find sources of info for this topic? Any reference to books, forums, websites, institutes, are welcome.

Thanks in advance for your help, kregards,