Learn Hardcore Croatian: Vlak je duži od autobusa. - The train is longer than the bus.

More examples: od grada (from/than the city), od brata (from/than the brother).
With pronouns, you also use genitive: od mene, od tebe, od njega, od nje, od nas, od vas, od njih.

What is je doing here? Do we need it?

Je is the 3rd person singular of the verb biti (to be): “is.” It’s required in a normal sentence. It’s also a clitic, so it usually sits in “second position” in the clause:

Neutral: Vlak je duži od autobusa.
With fronted emphasis: Duži je vlak od autobusa. You might see je omitted in headlines or notes, but in full sentences you should include it.

Why is it duži and not dug?

Because you’re making a comparison (“longer than”), so you need the comparative form.

Positive: dug (long)
Comparative: duži / dulji (longer)
Superlative: najduži / najdulji (the longest)
Here duži is masculine singular to agree with vlak (a masculine noun). Feminine would be duža, neuter duže.

Is duži correct in Croatian, or should it be dulji?

Both are used and understood. In Croatian, many style guides prefer dulji in formal standard language, while duži is extremely common in everyday speech and widely accepted. You’ll hear both in Croatia.

Superlatives follow the same split: najdulji / najduži.

Can I write the sentence with dulji instead?

Yes: Vlak je dulji od autobusa. That’s fully correct and a bit more “by-the-book.”

Can I use nego instead of od for “than”?

General rule of thumb:

With a noun after a comparative, Croatian most typically uses od + genitive: duži od autobusa. This is the safest, most neutral choice.
Nego is common before clauses or with certain structures: duži nego što misliš; radije vlak nego autobus (rather train than bus).
With pronouns, you’ll hear both: viši od mene (genitive) and viši nego ja (nominative). The od + genitive version is the default neutral choice.
With numbers/amounts, use od: više od deset, not usually više nego deset.

Is the word order fixed, or can I move things around?

You can move parts for emphasis, but keep the clitic je in second position:

Neutral: Vlak je duži od autobusa.
Emphasizing the adjective: Duži je vlak od autobusa.
Emphasizing the comparison: Od autobusa je vlak duži.
All are grammatical; the first is the most neutral.

Does od autobusa mean one bus or buses in general?

It can be ambiguous out of context because the genitive singular and genitive plural of autobus are both autobusa. Context usually clarifies. If you need to be explicit:

One bus: od jednog autobusa
Buses (in general): od autobusa (context), or od svih autobusa if you mean all buses.

How do I make it plural or change gender?

Plural subject: Vlakovi su duži/dulji od autobusa. (Trains are longer than buses.)
Feminine subject: Lađa je duža/dulja od autobusa.
Neuter subject: Krilo je duže/dulje od autobusa.
The adjective agrees with the subject (not with the noun after od).

How would I say “The train is 10 meters longer than the bus”?

Vlak je 10 metara duži/dulji od autobusa.
Note the case after numbers: with 5 and above you use genitive plural (metara). With 2–4 it’s metra: 2 metra, 3 metra, 4 metra.

How can I say “much longer” or “a bit longer”?

Use intensifiers before the comparative:

puno/znatno/bitno/znatno duži/dulji = much/considerably longer
nešto/malo duži/dulji = a bit/a little longer
daleko duži/dulji = far longer

What’s the difference between dug and dugačak?

Both can mean “long” for physical length. Dugačak is often a bit more colloquial or vivid. Importantly, the comparative of dugačak is still duži/dulji (not “dugačkiji”).

Vlak je dug/dugačak.
Vlak je duži/dulji od autobusa.

How do I compare durations instead of physical length?

Use the adverb (longer in time): dulje/duže.

Put vlakom traje dulje/duže nego autobusom. = The trip by train lasts longer than by bus.
In Croatian, dulje is often recommended; duže is also very common.

How do I say “as long as the bus”?

Use equality comparison:

Vlak je dug kao autobus.
Vlak je dug koliko i autobus.
For “not as long as”: Vlak nije tako dug kao autobus.

Are there articles in Croatian? How do I say “the train” vs “a train”?

Croatian has no articles. Vlak can mean “the train” or “a train” depending on context. To be specific, use demonstratives:

ovaj vlak (this train), taj vlak (that train), onaj vlak (that train over there)
Vlak je duži od tog autobusa. = The train is longer than that bus.

Is vlak ever voz?

Yes, that’s a regional/standard difference. In Croatia the standard word is vlak. In Serbian the standard is voz. In Bosnia and some other areas, both are heard. Your sentence is standard Croatian.

What do pronouns look like after od in comparisons?

Use genitive forms: od mene, od tebe, od njega, od nje, od nas, od vas, od njih.

On je viši od mene. = He is taller than me.
With nego, you’ll often see nominative: On je viši nego ja. Both are common; od + genitive is the default neutral option.

Any pitfalls to avoid, like using the wrong case with the comparison?

Don’t use instrumental after the comparison: say od autobusa, not “autobusom.”
Keep agreement: the comparative adjective agrees with the subject, not with the noun after od.
Don’t drop je in normal sentences.

How do I pronounce the tricky parts?

Vlak: one syllable with an initial consonant cluster; the v is lightly voiced.
ž in duži sounds like the s in English “measure.”
autobusa is four syllables: a-u-to-bu-sa (the au is pronounced as two vowels in sequence).