locomotive

巨大的蒸汽机车占据了整个车间。

The massive steam ___locomotive dominates the workshop.

这台老式蒸汽机车现在被放在博物馆展出。

The old steam ___locomotive is now on display in the museum.

教育改革成为了推动社会进步的火车头。

Educational reform became the ___locomotive behind social progress.