noun
train; long-distance train
Commonly used for trains, especially long-distance or intercity trains. In modern Japanese, 電車 is more common for local electric trains, but 汽車 is still used for steam or long-distance trains, and in set phrases.
汽車で北海道まで旅行した。
I traveled to Hokkaido by train.
この駅には一日に数本しか汽車が停まらない。
Only a few trains stop at this station each day.
noun
steam train
Original meaning; now mostly historical or nostalgic. Refers specifically to steam locomotives. In modern contexts, 蒸気機関車 is more precise.
博物館で昔の汽車の模型を見た。
I saw a model of an old steam train at the museum.
電車 is the common word for electric trains, especially local and commuter trains. 汽車 often implies a longer-distance or older-style train, and can specifically mean a steam train.
列車 is a formal term for a train as a scheduled service. 汽車 is more colloquial and can evoke a nostalgic or long-distance feel.
Combination of 汽 (steam) and 車 (vehicle), originally referring to steam-powered trains. The meaning broadened to include trains in general.