A bridge is 1,200 meters long, and a train travels 380 meters per minute when passing the bridge. It takes 4 minutes from the time the locomotive drives onto the bridge to when the train leaves the bridge. How long is the train body?
一座大桥长1200米，一列火车通过大桥时每分钟行380米，从火车头开上桥到火车尾离开桥共需要4分钟．这列火车车身长多少米？
<gadget id="calculator">4 * 380</gadget>
<output>1_520</output>

<gadget id="calculator">1_520 - 1_200</gadget>
<output>320</output>

<result>320</result>