Inside transport is not going to affect the city growth. Poeple can easily walk within 20 minutes from one end of the city to the other. They can get everywhere without public transport. So for the city it makes no difference.
Inside transport has 2 functions: get poeple arround FASTER, so they spend less time walking, and therefor have more time to go to take a train to another city. And, you get rich by transporting those poeple faster then they can walk… until automobile it taking over.