De trein is vertraagd, daardoor komen we te laat.

Because trein is a de-word in Dutch. Nouns in Dutch take either de or het, and this is something you usually have to learn with the noun.

So:

• de trein = the train

There is no special reason visible in this sentence; it is simply the correct article for trein.

Is vertraagd means is delayed.

This uses:

• is = is
• vertraagd = delayed

In Dutch, this is a very normal way to describe the state of something:

• De trein is vertraagd. = The train is delayed.

It works much like English. You are not saying that the train itself actively delayed something; you are describing its condition.

Vertraagd means delayed.

It comes from the verb vertragen, which means to delay or to slow down. In this sentence, vertraagd functions like an adjective/past participle describing the train.

Compare:

• Een vertraagde trein = a delayed train
• De trein is vertraagd = the train is delayed

So here it tells you the train is not running on time.

Daardoor means because of that, as a result, or therefore, depending on context.

In this sentence:

• De trein is vertraagd, daardoor komen we te laat.
• The train is delayed; because of that / as a result, we are arriving late.

It links the two ideas by showing cause and result:

1. the train is delayed
2. as a result, we are late

This is a very common question.

• daardoor = because of that / as a result of that
• daarom = that is why / for that reason

They are very close in meaning, but daardoor points more directly to a cause-effect relationship.

In your sentence, daardoor fits very naturally:

• De trein is vertraagd, daardoor komen we te laat.

You could also hear:

• De trein is vertraagd, daarom komen we te laat.

That is also understandable and often acceptable in everyday Dutch, but daardoor emphasizes the direct consequence a bit more.

Because Dutch main clauses usually follow the verb-second rule.

That means the finite verb must come in the second position of the clause. If you begin the clause with something other than the subject, the subject moves after the verb.

So:

• normal order: We komen te laat.
• with daardoor first: Daardoor komen we te laat.

Pattern:

• We komen te laat.
• Vandaag komen we te laat.
• Daardoor komen we te laat.

This inversion is very normal in Dutch and is one of the key word-order patterns learners need to get used to.

Yes. That is also correct.

Compare:

• Daardoor komen we te laat.
• We komen daardoor te laat.

Both mean roughly the same thing, but the emphasis changes slightly.

• Daardoor komen we te laat.
  This puts more focus on the consequence link: as a result, we are late.
• We komen daardoor te laat.
  This keeps the basic subject-first order and sounds a bit more neutral in flow.

So the sentence in your example starts with daardoor to highlight the cause/result connection.

In Dutch, te laat is the normal expression for too late or late in the sense of not on time.

So:

• te laat komen = to arrive late / to be late

Even though te often means too in a literal sense, in this expression you should learn te laat as a fixed phrase.

Examples:

• Ik kom te laat. = I’m late.
• We komen te laat. = We are late.
• Hij was te laat op school. = He was late for school.

Just laat exists too, but te laat is the usual phrase when someone or something misses the expected time.

The comma separates two closely connected clauses:

• De trein is vertraagd
• daardoor komen we te laat

It helps show a pause and makes the cause-result structure clearer.

In English, you might write:

• The train is delayed, so we’re late. or
• The train is delayed; as a result, we’re late.

Dutch punctuation can vary a little depending on style, but the comma here is very natural and helps readability.

They are related, but they describe different things.

• vertraagd describes the train
• te laat describes us

So:

• De trein is vertraagd = the train is delayed
• We komen te laat = we arrive late / we are late

A delayed train causes people to arrive late, so the sentence shows a chain of events:

1. the train is delayed
2. therefore, we are late

That distinction is important, because Dutch uses different expressions for the train’s schedule problem and the people’s late arrival.