Split and moved as not at all related to original topic, or indeed original entire forum section.
There is, and it's precisely to link the game on both devices to the same email or social media account. If you've already done this, then either there's a technical problem (maybe one device is Android and the other iOS?) or you've inadvertently connected them to different accounts. In either case you'll need to submit a support ticket and ask Pixel nicely to fix for you.
https://portal.pixelfederation.com/en/trainstation2/support
If you haven't connected one or other of the accounts yet, we can tal you through doing that.