This is from the World Bank. And it’s surprisingly good. It is primarly focused on state run systems, but does include a lot of content that is applicable to the US and Canada.
It coveres a lot of basics, such as gauge, track structure, etc. More importantly, it goes in to things such as cost behavior, pricing (Ramsey pricing is a must!), the need for a market orientation, etc. I don’t agree with everything they say. But it is a pretty good coverage of the important aspects of operating railroads in a financially viable way.
Enjoy if you so desire:
Edit to add an excerpt:
'Volumes have been written to show that railway rates ought to be based on the costs of carriage…such a basis is impossible, as no one knows, or can know, what the cost of carriage is. Cost of carriage of a particular item may mean the additional cost of carrying that item; this is normally so small as to be negligible. It may mean the additional cost plus a fair share of the standing costs of the organization… an arbitrarily estimated proportion of a sum that can only be ascertained very roughly.’
I really wish more people understood that. Now, and in the past. It would, and would have, prevented a whole lot of trouble.