Basically it is A-Train made to be playable on Nintendo 3DS.
Originally planned for 2011, A-Train 3D was released in Japan on February 13, 2014, in North America on April 14, 2015, and in Europe on April 16, 2015 as A-Train: City Simulator. It was published by Natsume for the Nintendo eShop on Nintendo 3DS. Nintendo eShop pre-orders also received the soundtrack
Source: Wikipedia, "A-Train", available under the CC-BY-SA License.