This looks extremely promising, especially since development on Third Rail seems to have stalled (no updates on progress since mid-last year). It’s being developed by small New Zealand-based studio, Dinosaur Polo Club (great name and logo!). Here’s the preamble from their website:
Mini Metro is a minimalist subway simulation game about designing efficient subway networks. The player must constantly redesign their line layout to meet the needs of a rapidly-growing city.
The game, currently available as a rough and ready alpha version (that’s pre-beta, folks!), currently has four maps – London, New York, Paris and one other that I haven’t identified as yet. Each map in the game looks like that of its real life equivalent, right down to the colours used to represent routes: a neat touch! That’s London seen in the mesmerising GIF above.
In short, I want to play this right now. Hurry up and take my money.