The old-fashioned diners on this train still maintain their mid-century charm.

diners 是 diner 的复数形式。diner 来自动词 dine（用餐）加后缀 -er 构成，原指"用餐者"，后来特指"餐车"或"小餐馆"，尤其指美国20世纪中期风格的复古餐厅。