A bridge is 2400 meters long. When a train passes the bridge, it travels 940 meters per minute. It takes 3 minutes from the front of the train to the bridge and the rear of the train to leave the bridge. How long is the train in meters? Tip: The distance traveled by the train from the front of the train to the bridge to the rear of the train = bridge length + train length.
一座大桥长2400米．一列火车通过大桥时每分钟行驶940米，从车头上桥到车尾离桥共需3分钟，这列火车长多少米？提示：火车行驶从车头上桥到车尾离桥所行驶的路程=桥长+火车长．
<gadget id="calculator">3 * 940</gadget>
<output>2_820</output>

<gadget id="calculator">2_820 - 2_400</gadget>
<output>420</output>

<result>420</result>