《明史·志·卷六十八》
成化十三年，听从甘肃总兵官王玺的奏请，制造雷火车，中间立有枢轴，旋转发炮。
十三年，从甘肃总兵官王玺奏，造雷火车，中立枢轴，旋转发炮。
In the thirteenth year of Chenghua, thunder firecarts were created upon the request of Wang Xi, the commanding military officer of Gansu. They had a central axis that could be rotated to fire cannons.