Ο σταθμός είναι ένα χιλιόμετρο μακριά.

Because σταθμός is a masculine noun in its dictionary form, so in the subject position it takes the masculine nominative article ο:

• ο σταθμός = the station

το is the neuter article, so it would not match σταθμός.

Also note that σταθμός here is the subject of the sentence, so it appears in the nominative case. You may see τον σταθμό in other sentences when it is the object, for example:

• Βλέπω τον σταθμό. = I see the station.

Because χιλιόμετρο is a neuter noun in Greek.

So the correct form is:

• ένα χιλιόμετρο = one kilometer

The article/number word has to agree with the noun’s gender:

• masculine: ένας
• feminine: μία / μια
• neuter: ένα

Since χιλιόμετρο is neuter, you use ένα.

Here μακριά means far or away.

In this sentence, it works like an adverb, describing distance:

• είναι μακριά = is far / is far away

So:

• Ο σταθμός είναι ένα χιλιόμετρο μακριά. = The station is one kilometer away.

A useful distinction:

• μακριά = far, far away (adverb)
• μακρινός / μακρινή / μακρινό = distant (adjective)

So Greek prefers μακριά in this kind of sentence, rather than using an adjective directly.

In this sentence, Greek is simply stating the distance as one kilometer away, without explicitly saying from here or from us.

That reference point is understood from context.

If you want to make it explicit, you can say:

• Ο σταθμός είναι ένα χιλιόμετρο μακριά από εδώ. = The station is one kilometer away from here.

So the shorter sentence is completely natural when the reference point is obvious.

Yes, in a normal standard Greek sentence like this, είναι is needed.

• Ο σταθμός είναι... = The station is...

Greek usually does not omit the verb to be in the way Russian or some other languages do in the present tense.

So:

• Ο σταθμός ένα χιλιόμετρο μακριά would sound incomplete in standard Greek.

This is the most natural order for saying a distance:

• ένα χιλιόμετρο μακριά = one kilometer away

Greek word order is somewhat flexible, but this order sounds neutral and standard.

You may also hear variations depending on emphasis, but the given version is the safest one for learners.

For example, if you move things around, the sentence may still be understood, but it can sound more marked or less natural.

Yes. Since the distance is one kilometer, Greek uses the singular:

• ένα χιλιόμετρο

If it were more than one, Greek would use the plural:

• δύο χιλιόμετρα = two kilometers
• τρία χιλιόμετρα = three kilometers

So the pattern is:

• ένα χιλιόμετρο
• δύο/τρία/τέσσερα... χιλιόμετρα

A rough pronunciation guide is:

• Ο σταθμός είναι ένα χιλιόμετρο μακριά
• o stath-MOS EE-ne E-na hilyo-ME-tro ma-kree-A

A few helpful notes:

• θ sounds like th in think
• χ sounds like a rough h / kh sound, not like English ch
• ει in είναι is pronounced like ee
• the stressed syllables are:
  • σταθμός
  • είναι
  • χιλιόμετρο
  • μακριά

Very often, yes, in this kind of sentence.

Greek commonly says:

• [place] είναι [distance] μακριά

Examples:

• Το σπίτι είναι πέντε λεπτά μακριά. = The house is five minutes away.
• Το χωριό είναι δέκα χιλιόμετρα μακριά. = The village is ten kilometers away.

So this structure is very useful and worth learning as a set pattern.

That would sound unnatural.

The natural Greek order is:

• Ο σταθμός είναι ένα χιλιόμετρο μακριά.

The distance phrase normally comes before μακριά.

So for learners, it is best to remember the chunk:

• είναι + distance + μακριά

It is in the accusative singular, although in this particular neuter form it looks the same as the nominative.

That is common in Greek with measurements and durations. The distance expression functions a bit like an object of measure:

• ένα χιλιόμετρο

Because χιλιόμετρο is neuter, the nominative and accusative singular are identical in form, so you do not see a visible change.

This is one reason Greek learners sometimes do not notice the case here.

The phrase ένα χιλιόμετρο μακριά is specific: it gives the actual distance, so it means one kilometer away.

If you wanted only The station is far, you would say:

• Ο σταθμός είναι μακριά.

Adding ένα χιλιόμετρο makes it more precise.