At the conductor's whistle the engine-driver starts his locomotive-engine.

乘务员哨声一响， 司机开动机车。

《新英汉大辞典》

When the locomotive is traveling at a constant speed or idling, the battery rather than the diesel engine can power the motor.

当火车头在相对恒定速度下前进或者空转时，这时电池就为马达提供能量，柴油发动机不工作。

youdao

Thomas is -strictly speaking -a "side tank engine" -a steam locomotive that has tanks arranged on either side of the boiler.

严格地讲，这个叫做托马斯的火车头是一个两边都装有水和燃料罐的蒸汽火车。

youdao

They travelled in coaches pulled by an 1898-built steam engine, known as Met Locomotive No 1.

BBC: London

The company identified 17 products that met its standard of providing "significant and measurable environmental performance advantages, " including a Lexan film that replaces conventional paint, Harmony water-conserving washing machines, the new fuel-efficient GEnx jet engine and GE's Evolution locomotive, a 208-ton, 4, 400hp workhorse that burns 3% less fuel and puts out 40% less pollution than its immediate predecessor.

FORBES: Magazine Article

The engine is the result of an 18-year project to build the locomotive and return it to main line service.

BBC: Loco makes historic main line run