I've been commuting for the last couple of months and this has been puzzling me as it's not something I really understand or have ever seen explained.

Two things that I think I understand:

(a) Track (and maybe stations as well?) is maintained by Network Rail, which is a non-profit owned by the Government
(b) The various rail companies bid for the rights to run franchises/routes and pay the government for this

My season ticket allows me to take trains by two different operators (East Midlands and First Capital Connect) between my home station and St Pancras in London.

Where did the money go when I paid for this ticket? Does it go to the train companies, Network Rail or someone else? How do companies make money on routes if the latter? Why is (at least, according to a Standard article I read the other week) responsible for supplying train cars to the companies that run the franchises?

I thought for a while that it might be like London buses, that the money might go into a central point of the transit authority and the individual companies are subcontracted to run the routes and nothing else, but that can't be the case because they're paying for the franchises in the first place, surely?