Prima di tornare a casa, controllo l’orario del treno.

In Italian, prima di + infinitive means before doing something.

So:

• prima di tornare = before returning / before going back

You normally need di before the infinitive here.

Examples:

• Prima di uscire, chiudo la porta. = Before going out, I close the door.
• Prima di mangiare, mi lavo le mani. = Before eating, I wash my hands.

Because after prima di, Italian uses the infinitive when the subject is the same as in the main clause.

In this sentence, the person who checks the timetable is also the person who returns home:

• (io) controllo
• (io) tornare

So Italian says:

• Prima di tornare a casa, controllo...

If the subject changes, Italian usually uses prima che + subjunctive instead:

• Prima che lui torni a casa, controllo l’orario.

Italian often drops subject pronouns because the verb ending already shows who is doing the action.

• controllo = I check
• controlli = you check
• controlla = he/she checks

So io is not necessary unless you want emphasis or contrast:

• Io controllo, tu aspetti. = I check, you wait.

In your sentence, controllo by itself already means I check.

Controllo is the 1st person singular present tense of controllare.

So:

• controllare = to check
• controllo = I check / I am checking

In Italian, the present tense can often translate both the simple present and the present continuous, depending on context.

A casa is a very common fixed expression meaning home or to/at home.

So:

• tornare a casa = to return home
• essere a casa = to be at home

Italian usually does not use the article here when casa means home in a general sense.

But if you mean a specific house/building, you may use an article:

• Vado alla casa di Marco. = I’m going to Marco’s house/home.

Because orario begins with a vowel, the definite article becomes l’.

So:

• l’orario = the timetable / the schedule

This is called elision.

Compare:

• il treno = the train
• l’orario = the timetable

The apostrophe shows that the article has been shortened before a vowel.

No. They are related, but they are not the same word.

• ora = hour, time, now
• orario = timetable, schedule, hours

In this sentence, l’orario del treno means:

• the train timetable
• or the train schedule

So orario is the correct word because we are talking about scheduled train times, not just the general idea of time.

Del is the contraction of di + il:

• di = of
• il = the
• del = of the

So:

• l’orario del treno = the timetable of the train / the train timetable

This structure is very common in Italian for expressing relationships between nouns.

Examples:

• la porta della casa = the door of the house
• il colore del mare = the color of the sea

Yes. That is also correct.

Italian is fairly flexible with word order, especially for adverbial phrases like prima di tornare a casa.

So both are natural:

• Prima di tornare a casa, controllo l’orario del treno.
• Controllo l’orario del treno prima di tornare a casa.

Putting prima di tornare a casa at the beginning gives it a little more prominence, like setting the scene first.

Because the sentence begins with an introductory phrase:

• Prima di tornare a casa, ...

In Italian, as in English, a comma is often used after this kind of opening phrase to make the sentence easier to read.

It is especially common when the introductory phrase comes first. If the phrase comes later, the comma is usually not needed:

• Controllo l’orario del treno prima di tornare a casa.

Not in this sentence.

When the subject is the same, Italian normally uses:

• prima di + infinitive

So:

• Prima di tornare a casa... = correct

Prima che is used when there is a different subject, and the verb after it normally goes in the subjunctive:

• Prima che io torni a casa, telefonami.
• Prima che lui parta, parlo con lui.

So prima che torno is not the normal choice here.

They are very similar. Both can mean to return or to go back.

• tornare
• ritornare

In everyday Italian, tornare is extremely common and often the more natural choice.

Examples:

• Torno a casa. = I’m going home / I’m returning home.
• Ritorno a casa. = also possible, but often a bit less common in ordinary speech.

So the sentence sounds very natural with tornare.