Im in the year 1980. For now, I don’t have much cargo transportation. But I recognized, that as soon as cars are available, they put some pressure on you to provide shorter intervals. So I countered that development with shorter but more trains. I have 4 to 6 trains per line, 3 min Intervalls. You could also destroy streets or make the longer to gain advantage over private automotives.
I also extended my net, running 4 train lines each with 3 to 9 stops connecting almost every city on the middle sized map. To increase the amount of passengers, I build a local tram service in every city starting from the train station and going through the middle of the city in one line (no circle line).
But I noticed, that it’s quite hard to run a realistic long intercity service for example with tgv’s. Therefore I currently start to build a cargo line. To run it profitable, I know that I have to transport the goods to more than one single city. Because as soon as you create enough demand in form of reachable markets for a steel production, it will increase its size and make longer transportation trains possible which have a higher profit margin.