Breakdown of Die beiden küssen sich am Bahnhof.
der Bahnhof
the train station
an
at, on (vertical) / to (addressee) / of (in quantity/stock expressions)
beide
both
küssen
to kiss
Questions & Answers about Die beiden küssen sich am Bahnhof.
Why does the sentence use Die beiden instead of Die zwei?
While die zwei is grammatically fine and sometimes used, die beiden is the standard, most natural way to say 'the two of them' or 'both of them' in German when referring to a specific, known pair.
Since they are kissing each other, shouldn't it be einander instead of sich?
You can use einander, but it sounds a bit stiff here. German frequently uses the reflexive pronoun sich to mean 'each other' (a reciprocal action) when the context makes it obvious, as it naturally does with kissing.
Why use the preposition am rather than im for 'at the station'?
Am (a contraction of an dem) is the standard way to say you are 'at' a transit hub like a train station or an airport. If you used im Bahnhof, you would be putting heavy emphasis on being physically indoors inside the station building.