Learn Hardcore Czech: Zítra pojedeme vlakem, který odjíždí z hlavního nádraží v šest ráno. - Tomorrow we will go by a train which departs from the main station at six in the morning.

Jezdit is the repeated / habitual form (going regularly, back and forth), so budeme jezdit would mean we will (regularly) travel or we’ll be commuting, which is a different meaning from one specific trip tomorrow.

Could we also say Zítra jedeme vlakem? What is the difference between jedeme and pojedeme?

Both are possible, but there is a nuance:

Zítra pojedeme vlakem – neutral, straightforward future: We will go by train tomorrow (one trip).
Zítra jedeme vlakem – present tense used for a fixed plan or arrangement in the (near) future, similar to English We are going by train tomorrow.

So jedeme can be present (we are going now) or scheduled future (we’re going tomorrow), while pojedeme is clearly future and one‑off.

Why is there no my for we? Why not My zítra pojedeme vlakem?

Czech very often drops subject pronouns, because the verb ending already shows the person and number:

pojedu = I will go
pojedeš = you (sg) will go
pojedeme = we will go

So Zítra pojedeme vlakem already clearly means we will go by train tomorrow.

You can say My zítra pojedeme vlakem if you want to emphasise we (as opposed to someone else), but in neutral speech the my is usually omitted.

Why is it vlakem and not vlak? What case is this?

Vlakem is the instrumental case of vlak (train).

The instrumental is used without a preposition to express means of transport and means or tools in general:

jet vlakem – to go by train
jet autobusem – to go by bus
psát perem – to write with a pen

Saying pojedeme vlak would sound wrong; it would literally be like saying we will go train instead of we will go by train.

Could we say pojedeme ve vlaku instead of pojedeme vlakem?

No, that would not mean the same thing.

pojedeme vlakem – we will go by train (means of transport)
pojedeme ve vlaku – literally: we will go in the train; grammatically possible, but it sounds odd and unnatural in this context. You would only use ve vlaku when you really want to talk about being inside the train (e.g. budeme sedět ve vlaku – we will sit in the train).

For the normal expression go by train, you should always use jet vlakem / pojedeme vlakem.

What does který refer to, and why is it který and not které?

Který is a relative pronoun introducing the clause který odjíždí z hlavního nádraží v šest ráno.

It refers back to vlak (train):

vlak is masculine inanimate singular
therefore the pronoun is also masculine singular nominative → který

You might be tempted to connect který with nádraží (which is neuter, and would take které), but grammatically it refers to vlak, not to nádraží. The meaning is the train that departs from the main station at six in the morning.

Why is there a comma before který?

In Czech, a comma is used before relative clauses introduced by words like který, co, že when they add extra information about a noun.

Here, který odjíždí z hlavního nádraží v šest ráno is a relative clause describing vlak:

Zítra pojedeme vlakem, který odjíždí…

So the comma is required, just as in English:

Tomorrow we’ll go by the train, which leaves from the main station at six in the morning.

Why is odjíždí in the present tense if the departure is in the future?

Czech, like English, can use present tense to talk about timetabled or scheduled future events.

Vlak odjíždí v šest ráno. – The train leaves at six in the morning.
Příští týden letím do Londýna. – I am flying to London next week.

So který odjíždí z hlavního nádraží v šest ráno = which leaves from the main station at six in the morning, even though the whole situation is in the future (zítra).

You could also say vlak odjede v šest ráno (perfective odjede, simple future), but odjíždí is the normal wording for timetables and regular departures.

Why is it z hlavního nádraží, not od hlavního nádraží or z hlavní nádraží?

Several things are happening here:

Preposition:
- z means from, out of and is used when something starts at or inside a place:
  - z domu – from (out of) the house
  - z nádraží – from the station
- od is more from near / from the vicinity of:
  - od domu – from (near) the house, from in front of the house
    For a train departing from a station, z nádraží is the normal choice.
Case:
- z requires the genitive case.
- hlavní nádraží (main station) in the genitive becomes z hlavního nádraží.
Why not z hlavní nádraží?
- The adjective has to agree in case with the noun. Genitive singular of hlavní nádraží is z hlavního nádraží, not z hlavní nádraží.

Why does hlavní change to hlavního here?

Hlavní is an adjective meaning main, and it must agree in gender, number, and case with nádraží.

Nominative: hlavní nádraží – the main station
Genitive (after z): z hlavního nádraží – from the main station

So the genitive singular form of the adjective is hlavního here. The noun nádraží is neuter; in the genitive singular it keeps the same form (nádraží), but the adjective changes to hlavního.

Why is it v šest ráno and not v šesti ráno? What case is šest?

When you talk about clock time with v meaning at, you use the accusative of the number:

v jednu – at one
ve dvě – at two
v pět – at five
v šest – at six

For the number šest, the accusative is the same as the nominative: šest (not šesti).

So v šest ráno literally means at six (o’clock) in the morning.

If you said v šesti, that would be locative and would mean something else entirely (and not make sense as a time expression).

Why is ráno without a preposition? Why not v ráno?

Ráno in this sentence is an adverb meaning in the morning, not a bare noun morning.

So:

v šest ráno – at six in the morning
ráno here works like English tomorrow or today: you do not say in tomorrow or in today.

If you want to use ráno as a noun with a preposition, you can say:

v ráno is not idiomatic; instead:
brzy ráno – early in the morning
tohle ráno – this morning (rare, more commonly dnes ráno – today in the morning)

Is the word order fixed? Could we say Vlakem pojedeme zítra… or …odjíždí v šest ráno z hlavního nádraží?

Czech word order is relatively flexible, and several variants would be correct, though some sound more natural than others.

For example, you could say:

Zítra pojedeme vlakem, který z hlavního nádraží odjíždí v šest ráno.
Vlakem pojedeme zítra, vlak odjíždí z hlavního nádraží v šest ráno.

The basic tendencies:

Time expressions like zítra and v šest ráno often appear near the beginning or end of the clause.
New / less important information tends to come later.
The given sentence is a very natural, neutral word order.

So minor rearrangements are possible, but the original version is the most typical.