求翻译：　　因为履带车在土地上行驶得很平稳，于是苏显文改用履带代替轮来驱动。为了适应山坡地上弯曲的地垄，苏显文又为机动犁加上了方向杆。该履带式机动犁重量适中，结构紧凑，各种部件搭配合理、科学，达到了省工、省力、省时又省钱的效果。是什么意思？

Tracked vehicles traveling on the land is very stable, so Su Xianwen switch to the track instead of the wheel to drive. In order to adapt to the curved ridge of the mountain slopes, Su Xianwen for motor plow with a direction lever. The crawler motor plow moderate weight, compact structure, the vario