Tunnel in hard rock may be excavated in whole section by using chiseling rock trolley to drill small holes.
在硬岩中中隧道可采用凿岩台车钻眼，进行全断面开挖。
2
The dual-point meshing in single-drive BF flexible-transmission device will promote its bearing capacity by two small pinions which are setting in a small slung trolley to driving big one altogether.