Mass transit enthusiasts would probably love OpenTTD. Instead of managing a city, you manage a transit company that operates ships, planes, trucks, buses, and most of all trains.

Cities grow as you serve them with more mass transit, which maybe is more optimistic than real life, but on the other hand the game also teaches you that tearing up half the city to install a massive train yard is very expensive and will make local politicians furious with you, requiring you to bribe them with cash (or reforestation campaigns..) if you want to continue construction in their city.

Unfortunately it's missing subways, but the trams provided by community extensions are a pretty decent substitute.