NLB-2000 internal combustion impact wrench is mainly used for tightening or loosening nuts on rail fastener fastening bolts and clamp plate fixing bolts during railway construction or maintenance operations. The machine adopts the energy superposition principle and uses the instantaneous peak torque to repeatedly impact the action to complete the tightening or loosening of nuts. The machine has a compact structure, light weight, and is easy to carry. It can complete the tightening and loosening of nuts on connecting bolts arranged in different directions such as vertical, horizontal, and inclined. Especially for nuts that are difficult to loosen due to rust and other reasons, using this wrench to operate has its unique effect.