The train travels 1,050 meters per minute. From the front of the train parallel to a road sign until the rear of the train leaves this road sign for 3 minutes, a motorcycle starts from this road sign at a speed of 1,200 meters per minute. 25 minutes after the motorcycle departs, it coincides with the front of the train. tied. Find the length of this train.
火车每分钟行1050米，从车头与一个路标并列到车尾离开这个路标3分钟后一辆摩托车以每分钟1200米的速度从这个路标出发，摩托车出发25分钟后，与火车的车头正好并列．求这列火车的长．
<gadget id="calculator">1_200 * 25</gadget>
<output>30_000</output>

<gadget id="calculator">25 + 3</gadget>
<output>28</output>

<gadget id="calculator">1_050 * 28</gadget>
<output>29_400</output>

<gadget id="calculator">30_000 - 29_400</gadget>
<output>600</output>

<result>600</result>