Yes.

This/that/these/those + noun gets the "the" in Hungarian. What's more, the this/that/etc. also gets conjugated.

Ez a vonat - This train
Ezek a vonatok - These trains
Ezzel a vonattal - With this train
And even: Ez alatt a vonat alatt - Under this train.

If you leave out the "a", the meaning changes:

Ez a vonat - This train
Ez vonat - This is a train
Ezek vonatok - These are trains

But one more twist. If you put extra emphasis on "vonat",
Ez a vonat - will mean "This is the train".
Ezek a vonatok - These are the trains

So, going back to literal, "This is a train is here" - makes no sense.

Same for Romanian. We don't use the demonstrative pronoun, even though we have it, we use the demonstrative adjective ! The formula is like this: Object+def. art.+dem. adj. Example: Mărul ăsta (this apple)

•Măr-object •-ul - definite article (yes, it's a suffix) •ăsta - dem. adj. (It has 4 forms for masculine and feminine, singular and plural: ăsta, asta, ăștia, astea) If we would use the demonstrative pronoun, it would be easier, but in day to day speech it isn't. Acest măr would be the other form. Mărul ăsta and acest măr mean both the same thing, but they are expressed differently ;)

I see. So if I understand correctly, in this case "van" is retained because it is answering the question of "Where?" And I gather that if the question were instead asking "What?" like "What color is the train?" then "van" would indeed be omitted. Is that right?

I honestly prefer this over the English; I think dropping the verb makes a lot of sense. I just want to do it correctly!