noun
platform, train platform
A1
Bahnsteig (der) means platform, especially a train platform at a station. It refers to the raised area where passengers board trains. Plural: Bahnsteige. It's a regular masculine noun; compound of Bahn + Steig. No special prepositions or auxiliary verbs (it's a noun).
Examples
Bitte warten Sie auf dem Bahnsteig hinter der Sicherheitslinie.
Please wait on the platform behind the safety line.
Unser Zug fährt auf Gleis 7, Bahnsteig 3.
Our train departs from track 7, platform 3.
Am Bahnsteig stand eine Frau, die verzweifelt telefonierte, weil ihr Zug verspätet angekommen war.
A woman stood on the platform, desperately making a phone call because her train had arrived late.
Details
Mnemonics
Imagine stepping onto a platform with a big number sign: that's the 'Bahnsteig'.
Bahn + stei(g) — 'steig' like 'step' (platform to step onto).
der — picture a male platform attendant calling out departures (der Bahnsteig).
Notes
Compound of 'Bahn' + 'Steig' (ramp/track area).