节，多用于指大卡车或者火车 辆多指小型车，或者一些自行车，三轮车，电动车

The English term "car" has two definitions: 1 a vehicle with four wheels and an engine, that can carry a small number of passengers. In this meaning, "car" = 汽车。We say 一辆汽车，not 一节汽车。 2 (used in American English) a train carriage. In this meaning, "car" = 车厢。We say 一节车厢，not 一辆车厢。

汽车 is car, 车厢 aiways means carriage/compartment

一辆汽车和一节车厢都是正确的。 但是两者不能互换。(you cant say 一节汽车 or 一辆车 ) cause, 汽车include 车厢 ，汽车is a whole, but 车厢just a part of it. hope my answer can help u understand.

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