Toget kører ikke videre, før alle er gået om bord.

Køre is broader than English drive. It is used for vehicles moving or operating, not just for a person driving a car.

So with a train, toget kører means something like:

• the train is running
• the train is going
• the train is continuing

In transport contexts, køre is extremely common for trains, buses, cars, and routes.

Danish often uses the simple present for future events, especially when they are scheduled, expected, or about to happen.

So Toget kører ikke videre can naturally mean:

• The train is not continuing
• The train will not continue

English often prefers will here, but Danish does not need a separate future form.

Videre means further, onward, or any further.

In kører videre, it means the train is continuing its journey rather than stopping here.

So ikke videre gives the sense of:

• not any farther
• not onward
• not on from here

Yes, før basically means before, but in the pattern ikke ... før, English usually translates it as not ... until.

So:

• Toget kører ikke videre, før ... = The train won’t continue until ...

This is a very common pattern:

• Jeg går ikke, før du kommer. = I’m not leaving until you come.

So the negative in the main clause changes how it is best translated into English.

Because the sentence focuses on a completed action. The train will not continue until the boarding is finished.

• alle går om bord = everyone boards / is boarding
• alle er gået om bord = everyone has boarded

The perfect form er gået makes it clear that the train waits for the result: everyone must already be on board.

With gå, Danish often uses være as the auxiliary when the verb expresses movement to a destination or a completed change of place/state.

So:

• Hun er gået hjem = She has gone home
• Alle er gået om bord = Everyone has boarded

By contrast, har gået often refers more to the activity of walking:

• Han har gået i to timer = He has walked for two hours

So here er gået om bord highlights that people have ended up on board.

Om bord means on board or aboard. It is a fixed expression used for entering or being on a train, ship, plane, and similar transport.

So gå om bord means:

• go on board
• board

You may also see ombord written as one word in some contexts, but the meaning is the same.

Because in a normal Danish main clause, the finite verb usually comes in second position, and sentence adverbs like ikke come after it.

So:

• Toget = subject
• kører = finite verb
• ikke = negation

This gives:

• Toget kører ikke videre

English needs do in many similar sentences, but Danish does not:

• English: The train does not continue
• Danish: Toget kører ikke videre

Because før alle er gået om bord is a subordinate clause, introduced by før.

In Danish subordinate clauses, the subject normally comes before the finite verb:

• alle er gået om bord

You often get inversion in main clauses, but not in subordinate clauses like this one.

Compare:

• Main clause: Nu går alle om bord.
• Subordinate clause: før alle går om bord

Here alle means everyone, with the noun understood from the situation.

In context, it means all the passengers who are supposed to board.

Danish often uses alle on its own when the group is obvious:

• Alle er klar. = Everyone is ready.
• Alle er gået om bord. = Everyone has boarded.

There are other possibilities. A very common alternative is stige på, especially for buses and trains.

For example:

• før alle er steget på

That also means before/until everyone has boarded / gotten on.

The difference is mostly style and nuance:

• gå om bord sounds a bit more formal or announcement-like
• stige på is very common in everyday language for getting on public transport