Пассажирка у окна читала книгу всю дорогу.

Пассажирка is the feminine form, so it means a female passenger. Russian past-tense verbs agree in gender, and here the verb is читала, which is also feminine.

• пассажир = male passenger / passenger in a general sense
• пассажирка = female passenger

So the sentence is specifically about a woman.

In the past tense, Russian verbs change for gender and number.

For читать (to read), the past forms are:

• читал = he read / was reading
• читала = she read / was reading
• читало = it read / was reading
• читали = they read / were reading

Because пассажирка is feminine, the verb must be читала.

This is about aspect, one of the most important parts of Russian verbs.

• читать / читала = imperfective: focuses on the process, ongoing action, or repeated action
• прочитать / прочитала = perfective: focuses on completing the action

In Пассажирка у окна читала книгу всю дорогу, the idea is that she spent the trip reading. The sentence emphasizes the activity during that time, not the fact that she finished the book.

If you said прочитала книгу, that would usually mean she finished the book.

Because it is the direct object of the verb читала. Direct objects often go into the accusative case.

• dictionary form: книга
• accusative singular: книгу

This change is typical for many feminine nouns ending in -а:

• книга → книгу
• газета → газету
• машина → машину

So читала книгу means was reading a book / the book.

Окна is in the genitive singular because it follows the preposition у.

The preposition у commonly means by, near, or sometimes at, and it requires the genitive case.

• окно = window
• у окна = by the window / near the window

So пассажирка у окна means the passenger by the window.

All three can mean something like near/by the window, but у окна is very natural and compact here.

Roughly:

• у окна = by the window, at the window
• около окна = near the window
• возле окна = near the window / next to the window

In this sentence, у окна sounds like a normal way to identify which passenger we mean: the passenger by the window.

It most naturally modifies пассажирка: the passenger by the window.

So the structure is basically:

• Пассажирка у окна = the passenger by the window
• читала книгу = was reading a book
• всю дорогу = the whole trip / all the way

Of course, in real life, being the passenger by the window also tells you where she was sitting, but grammatically it is attached to the noun phrase.

Всю дорогу means the whole trip, all the way, or the entire journey.

The noun is:

• дорога = road, way, trip, journey

Here it is in the accusative singular, and the adjective всю agrees with it:

• вся дорога = the whole road/trip (nominative)
• всю дорогу = the whole trip / all the way (accusative)

This is a very common Russian time-expression pattern.

Russian often uses the accusative case without a preposition to express duration of time.

So всю дорогу literally uses just the noun phrase, but functionally it means:

• for the whole trip
• all the way

Other similar patterns are:

• весь день = all day
• всю ночь = all night
• всю неделю = all week

So this is a normal Russian way to express how long something lasted.

Yes, Russian word order is flexible. This version sounds natural and fairly neutral.

It presents the information like this:

1. Пассажирка у окна — who we are talking about
2. читала — what she was doing
3. книгу — what she was reading
4. всю дорогу — for how long

You could rearrange it, but the emphasis would change:

• Всю дорогу пассажирка у окна читала книгу.
  Emphasizes the whole trip
• Книгу пассажирка у окна читала всю дорогу.
  Emphasizes the book
• Пассажирка у окна всю дорогу читала книгу.
  Also very natural; slightly stronger focus on duration before the verb phrase

So the original order is not the only possible one, but it is a very normal choice.

No, not by itself. Because читала is imperfective, it usually means she was reading or spent time reading the book. It does not tell us whether she finished it.

If you want to say that she finished it, Russian would usually use a perfective verb, for example прочитала книгу.

So:

• читала книгу = was reading a book / read a book for some time
• прочитала книгу = read the book completely / finished reading it

Russian has no articles like a or the. So книгу can mean either a book or the book, depending on context.

In an isolated sentence like this, English often chooses a book, because it sounds more natural if the book has not been mentioned before. But Russian itself does not mark that difference with an article.

Context decides:

• new information → often translated as a book
• already known/specific book → often translated as the book