Train Fever is a very detailed game, also all the inhabitants in your gameworld are individual acting. Not only trains and verhicles but also every individual can be followed too. During the later game stages the number of inhabitants can be grown into many thousands, especially on larger maps even 10 thousands. It is i.m.o. only advisable to play on the large maps if you have a very powerful computer. Else you can better play on mediocare or even small sized maps.