A bridge is 3600 meters long. A train passes the bridge at a speed of 2000 meters per minute. It takes 2 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?
一座大桥长3600米，一列火车以每分2000米的速度通过大桥，从车头上桥到车尾离桥共需2分，这列火车长多少米？
<gadget id="calculator">2_000 * 2</gadget>
<output>4_000</output>

<gadget id="calculator">4_000 - 3_600</gadget>
<output>400</output>

<result>400</result>