Learn Spanish (Spain): El tren acaba de llegar a la vía dos. - The train has just arrived at track two.

In Spanish, the phrase acabar de followed by an infinitive (like llegar) is the standard way to express that an action "has just" happened. You cannot use a direct translation of "just" (like solo or justamente) to communicate this idea of a recently completed action.

Could I use the present perfect and say ha llegado instead?

You could say El tren ha llegado (The train has arrived), but you would lose the specific meaning that it happened only a moment ago. To express that something "has just" happened, acaba de + infinitive is the most natural choice.

Why do we say vía dos instead of using the ordinal number segunda?

When identifying things like train tracks, hotel rooms, or pages by a specific number, Spanish places a regular (cardinal) number immediately after the noun. So, "track two" is la vía dos, just as "room three" would be la habitación tres.

Why does llegar use the preposition a in this sentence?

The verb llegar (to arrive) almost always takes the preposition a when stating a destination. While English speakers arrive "at" or "in" a place, in Spanish you generally arrive "to" (a) your destination, making it llegar a la vía.