Steam railways had their heyday in the 19th century.
19世纪是蒸汽机车的全盛时期。
heyday详细解释
hey.day n.(名词)The period of greatest popularity, success, or power; prime.极盛时期:繁荣、成功或力量的最高潮;全盛时期 来源:Perhaps alteration of heyda [exclamation of pleasure] 可能为 heyda的变化 [欢呼] probably alteration of Middle English hey [hey] 可能为 中古英语 hey的变化 [嘿]