From the technical point of view, this DLC is ok - it does not contains big issues and doesn't break the game mechanics. I faced only with few minor issues - a few times the colonist occasionally jumped from the train at the center of the map and suffocated cause there was no dome nearby. It has some issues with creating new trains - you can't see how many you ordered until they are created. Also, the interface of the train station is quite complicated, and it's now always clear why trains go empty. From the gameplay perspective, I don't find trains useful: yes, now you can transfer water and oxygen, and you colonist can live in one corner of the map and work in the extractor or cafe in the dom on the opposite side of the map and has only 10 point penalty, like in nearest dome. But trains and train stations are quite expensive and rails cost literally thousands tonnes of concrete. Railway half-map length costs twice Concrete more than Mohole Mine or Omega Telescope, so it's a quite not effective waste of resources, and it takes 6-7 sols to build it even after all resources were delivered. I found it much more efficient to build a micro dome near the extractor for your geologists rather than taking the railroad there, and what to do with it when the extractor runs out? But eventually, it's quite an interesting mechanic and you can have some fun with it.
