Nijedan autobus nije stigao na stanicu, pa idemo pješice.

Croatian commonly uses nijedan + singular noun to mean not a single…:

• nijedan autobus = not a single bus

You can also say it in plural:

• nijedni autobusi nisu stigli = no buses arrived

Both are correct; the singular version is very common when you want to stress “not even one.”

Croatian uses negative concord: when you have a negative word like nijedan (“no/none”), the verb is also negative (nije). So nijedan … nije … is the standard grammatical pattern, and it still means a single negation in English:

• Nijedan autobus nije stigao. = No bus arrived.

Because the subject here is grammatically singular: nijedan autobus (singular noun), so the verb is singular:

• nije stigao = did not arrive (singular)

If you use a plural subject, you switch to plural:

• nijedni autobusi nisu stigli (plural auxiliary + plural participle)

It’s the Croatian perfect (the usual past tense in conversation):

• nije = present of biti (“to be”) used as an auxiliary (negative form)
• stigao = past participle of stići (“to arrive”)

Pattern: (auxiliary biti) + past participle
Here: nije + stigao.

Yes—past participles agree in gender and number with the subject (especially in the perfect).

• autobus is masculine singular → stigao (masc. sg.)

Compare:

• Autobus je stigao. (masc. sg.)
• Tramvaj je stigao. (masc. sg.)
• Autobus i tramvaj su stigli. (masc. pl. mixed group)
• Autobusna linija je stigla. (fem. sg.)

With na, Croatian uses different cases depending on meaning:

• na + accusative = motion toward/onto → na stanicu (to the stop)
• na + locative = location at/on → na stanici (at the stop)

So:

• Nije stigao na stanicu. = didn’t arrive to/at the stop (as a destination)
• Nije na stanici. = isn’t at the stop

Here pa works like “so/therefore”, linking a cause to a consequence:

• …, pa idemo pješice. = …, so we’re going on foot.

zato can also mean “therefore/because of that,” but it often feels a bit more explicit:

• Nijedan autobus nije stigao, zato idemo pješice. Both are possible; pa is very common in everyday speech.

Croatian often uses the present tense for a near-future decision/plan, especially when it’s immediate:

• idemo pješice = we’re going (now), we’ll go on foot

You could also use future:

• ići ćemo pješice = we will go on foot (more neutral/explicit future)

Also, depending on context, Idemo! can mean “Let’s go!”, but in this sentence it’s simply “we go / we’re going.”

pješice is an adverb meaning “on foot / walking.”
It doesn’t need a preposition:

• Idemo pješice. = We’re going on foot.
• Došao sam pješice. = I came on foot.

Yes, Croatian word order is flexible, and changes usually affect emphasis:

• Nijedan autobus nije stigao… (neutral: “No bus arrived…”)
• Nije stigao nijedan autobus… (more emphasis on the fact of not arriving)

Both are correct.

Key pronunciation notes:

• nj in nijedan is like the ny in canyon (roughly): ni-je-dan
• š in pješice is sh as in ship
• ć in pješice is a soft “ch”-like sound (softer than English ch)

Approximate guide:

• Nijedan ≈ nee-YEH-dan
• pješice ≈ PYEH-shee-tseh (with a soft ć sound)

Because the sentence has two independent clauses: 1) Nijedan autobus nije stigao na stanicu
2) pa idemo pješice

The comma is standard when pa links clauses with a “so/therefore” meaning.