It is a MSE (Multi Super Express), so it is used in different limited Express route. (Or another word, Romance Car)

Why limited express run by Odakyu is called Romance Car? Well, people say that by taking the train, you can sit next to the stranger, and that is where love bloom (not on the battlefield).

Through service with Tokyo Metro Chiyoda Line

Through service with JR :( line to sightsee Mt. Fuji

Limited express go to Hakone Yumoto

And it has mh, pretty romantic?

Souce