bridge is 3600 meters long. A train passes the bridge at a speed of 900 meters per minute. It takes 5 minutes to leave the bridge from the rear of the train. What is the length of the train in meters?
座大桥长3600米，一列火车以每分钟900米的速度通过大桥，从车尾离开大桥要5分钟，求火车长是多少米？
<gadget id="calculator">5 * 900</gadget>
<output>4_500</output>

<gadget id="calculator">4_500 - 3_600</gadget>
<output>900</output>

<result>900</result>