The heart of Crotoonia's beginnings lie in Celgreb City and its surrounding areas. This bustling metropolis, located just a few several miles from the East Coast of the US, got its early beginnings as a medium sized market community, used to connect the various parts of the country together, like the western side of the Cliffstone Mountains (where the logging and mining industries were beginning to take off), Grofflen (where a planned shipping yard was beginning to take shape), and Bartlett Bay (which became greatly popular among fishermen). Overtime, as more and more people came flooding into the country, the small market community grew into a bustling city, where engines coming in and out from the nearby towns, and continue on to either America or beyond!
The city has many locations where the engines work, such as Celgreb City Central Junction (the terminus and main station for a majority of the railway lines), Celgreb City Freight Depot (where the majority of the goods traffic goes through and gets sorted, stocked, and delivered), the Celgreb City Tram Lines (where Daisy and Decka work), and Stateside Bridge (a girder bridge where engines cross over to America's railways).
- Celgreb's name is derived from animation cels.