Le train arrive à six heures et demie.

French usually needs an article before a noun in a normal sentence. So le train means the train.

Unlike English, where you can sometimes omit articles in certain contexts, French normally keeps them:

• Le train arrive... = The train arrives...
• Un train arrive... = A train arrives...

So le is not optional here.

Arriver is the infinitive, meaning to arrive.
In this sentence, the verb is conjugated to match le train:

• arriver = to arrive
• le train arrive = the train arrives

Because le train is third-person singular, French uses arrive.

French often uses the present tense for schedules, timetables, and fixed events, just like English can:

• The train arrives at 6:30.
• Le train arrive à six heures et demie.

This is a very natural use of the present in French when talking about planned or scheduled events.

Here, à means at, when giving a clock time.

• à six heures = at six o’clock
• à midi = at noon
• à minuit = at midnight

So in this sentence, à introduces the time when the train arrives.

Because it is six hours literally. In French, when telling time, you use heure in the plural for most times greater than one:

• une heure = one o’clock
• deux heures = two o’clock
• six heures = six o’clock

So six heures is the normal form.

Et demie means and a half, so six heures et demie means half past six or six thirty.

Examples:

• trois heures et demie = 3:30
• huit heures et demie = 8:30

It is the standard way to express :30 after the hour.

Because demie agrees with heure, which is feminine.

In six heures et demie, the word demie refers to heure:

• une heure et demie
• deux heures et demie
• six heures et demie

Since heure is feminine, French uses demie.

Compare:

• un demi-kilo = half a kilo
  Here demi comes before the noun and usually does not agree.
• une heure et demie = a half hour past one
  Here demie comes after and agrees with heure.

Yes. Six heures trente is also correct and means 6:30.

Both are common:

• six heures et demie
• six heures trente

Et demie is often a little more traditional or conversational, while trente is very straightforward and common too.

A careful pronunciation is approximately:

luh treh(n) ah-reev ah sees uhr ay duh-mee

A few helpful points:

• Le sounds like luh
• train has a nasal vowel; the n is not fully pronounced like in English
• arrive sounds like ah-reev
• heures sounds roughly like uhr
• et demie sounds like ay duh-mee

In natural speech, French flows together smoothly, so the sentence may sound more connected than the spelling suggests.

There is no major obligatory liaison that beginners especially need to worry about here.

You will mainly hear smooth connections between words:

• train arrive
• à six heures
• heures et demie

French speakers connect words naturally, but this sentence does not contain one of the most famous mandatory liaisons like les amis or vous avez.

Yes. Le train usually refers to a specific train that is known from the context.

For example:

• a train already mentioned
• the train someone is waiting for
• the scheduled train on a board or timetable

If you wanted to mean a train in a more general or indefinite way, you would usually say un train.

The word order is the standard French pattern:

subject + verb + time expression

• Le train = subject
• arrive = verb
• à six heures et demie = time phrase

This is very similar to English:

• The train arrives at 6:30.

So the structure is straightforward and common.