Welcome, Michal! It's always good to have people from the other side of the pond who take an interest in North American railroading (I say North American because these days, there isn't a lot to distinguish between Canadian and US railroading).
Unfortunately, you're not going to find everything you want in one place -- being able to use Google is going to be your best friend. Also, because things differ so much from one North American railroad to another, you might want to consider choosing a specific railroad to model, because you can look up specific models of locomotive, operating procedures, etc., and you can contact their historical society for equipment rosters, timetables, and so on.
A couple of other good sources of information: the Kalmbach Hobby Store sells dozens of excellent books on model railroading (modeling rolling stock and structures, and adopting real world operating procedures to your layout, as well as how to model specific industries), garden railroading, and real-world data. Several books on diesels are available, but the one that had line drawings and dimensions is out of print. The link is here:
https://kalmbachhobbystore.com/catalog/books?
A second excellent source is Model Railroad Hobbyist magazine. It is a free (for the basic subscription), on-line only publication that is loaded with articles on scratch building locomotives and structures, prototype operations, and yes, not one but TWO articles on freight car trucks. It is fully indexed so you can find articles easily, and all back issues are available on-line (read online or download). Their website is:
https://model-railroad-hobbyist.com/
Your research will be half the fun. Good luck!
Linear Mode
