This is the 1979th most frequent Japanese word.
のぼり
"のぼり" means "climbing," "ascending," or can refer to a "banner" or "flag" used for promotion.
In this sentence, 'のぼり' is used to refer to the act of climbing, specifically mountain climbing in this context.
私は山のぼりが好きです。
I like mountain climbing.
Here, 'のぼり' describes an upward direction, often used for trains going toward the central area of a region, such as towards Tokyo.
この電車はのぼりです。
This train is headed uphill.
In this context, 'のぼり' means banners or flags, often vertical banners displayed for events or promotions.