In this situation, are you approaching a railway crossing?

In the video you are driving on a dual carriageway in town along tram tracks; on the right there is a yellow triangle with a tram symbol - sign A-21 "tram". You are not approaching a level crossing. The answer is: no.

The Regulation on road signs and signals states that sign A-21 "tram" warns of a crossing over tram tracks, while a level crossing is warned of by other signs: A-9 "level crossing with barriers" with a fence symbol and A-10 "level crossing without barriers" with a locomotive symbol, supplemented by countdown markers G-1 and St Andrew's crosses G-3 or G-4. The difference matters in practice: before a level crossing, the Road Traffic Act requires you to exercise particular caution and make sure that no train is coming, and it prohibits entering when the barriers are coming down or a red light is on; before a tram crossing, particular caution applies, and at an uncontrolled junction of equal roads a tram has right of way regardless of its direction. A tram needs longer to brake than a car and cannot go around you, so you enter the tracks only when you have time to clear them. The symbol on the sign shows the type of crossing: a tram with a pantograph is A-21, a locomotive is A-10.

Legal basis: § 10 para. 3 and § 6 para. 1 and 2 of the Regulation on road signs and signals; Art. 25 para. 2 and Art. 28 para. 1 of the Road Traffic Act (Prawo o ruchu drogowym)