Liquid freights can be shipped in tank cars, or the liquids packed in containers can be hauled by gondola, reefer or boxcar. Perishables go by reefer. Smaller dry loads are the province of the boxcar, and anything too big for the boxcar goes by flat or gondola. Whimsey fans can invent their own peculiar cars. Among the few non-cargo trains would be firefighting trains, armored combat trains and maintenance of way.
Railways can be old or new.
Most are set within a particular era. Each era had a technological limit. For instance, prior to 1890, steam was the top of the line power source. Around 1910, electricity became more available. The gasoline engine was becoming available around 1905, and was almost common by 1910.