אני לא יכול לעלות על הרכבת בלי כרטיס.

In Hebrew, the verb to be is usually not expressed in the present tense.

So:

• אני יכול = I am able / I can
• literally, it is closer to I able

That is completely normal Hebrew.
If you wanted past or future, Hebrew would use forms of to be differently, but in the present tense it is usually left out.

Hebrew often expresses can with the word יכול, which literally means able.

So:

• אני יכול לעלות = I can get on / board
• literally: I am able to get on

This is one of the most common ways to say can in Hebrew.

Hebrew usually makes negation very simply by putting לא before the word or phrase being negated.

So:

• יכול = able / can
• לא יכול = not able / can't

This is the normal way to say cannot in modern Hebrew.

The word יכול must agree with the speaker.

For a male speaker:

• אני לא יכול לעלות על הרכבת בלי כרטיס

For a female speaker:

• אני לא יכולה לעלות על הרכבת בלי כרטיס

So the only change here is:

• יכול → יכולה

This is because Hebrew marks gender much more often than English does.

לעלות is the infinitive form, meaning to go up / to get on / to board, depending on context.

The prefix ל־ on an infinitive often corresponds to English to:

• לעלות = to get on / to board

After יכול (can / able), Hebrew normally uses an infinitive:

• אני יכול לעלות = I can get on

So this structure is very similar to English can + verb, even though the Hebrew infinitive literally contains to.

Yes, לעלות literally means to go up, but with the preposition על it often means to get on / board a vehicle.

So:

• לעלות על הרכבת = to get on the train
• literally something like to go up onto the train

This is a very normal Hebrew expression.
You will also hear similar patterns with buses, planes, and so on.

Because the expression לעלות על is the standard way to say get on / board.

Examples:

• לעלות על אוטובוס = to get on a bus
• לעלות על מטוס = to board a plane
• לעלות על רכבת = to get on a train

Even though על often means on, in this phrase you should learn לעלות על as one unit of meaning.

The prefix ה־ is the Hebrew definite article, meaning the.

So:

• רכבת = train
• הרכבת = the train

In this sentence, the speaker is referring to the train, not just any train.

Hebrew has no separate indefinite article like English a / an.

So:

• כרטיס can mean a ticket or just ticket, depending on context
• הכרטיס means the ticket

That is why:

• בלי כרטיס = without a ticket

The noun is indefinite simply because it does not have ה־.

בלי means without.

After בלי, Hebrew often uses a bare noun, especially when English would say without a/an + noun.

So:

• בלי כרטיס = without a ticket
• literally: without ticket

This is completely natural in Hebrew.

Sometimes Hebrew drops subject pronouns, but here אני is usually helpful and natural.

Why? Because יכול shows gender and number, but not person very clearly in the same way English verbs do.
So אני makes the subject explicit:

• אני לא יכול... = I can’t...

Without אני, the sentence could sound less clear unless the context already makes the subject obvious.

It can mean either, depending on context.

In this sentence, אני לא יכול לעלות על הרכבת בלי כרטיס most naturally means:

• I can’t get on the train without a ticket

This could imply:

• it is not permitted, or
• it is practically impossible because the rules require a ticket

If you wanted to emphasize not allowed, Hebrew often uses:

• אסור לי = I’m not allowed

So:

• אסור לי לעלות על הרכבת בלי כרטיס = I’m not allowed to get on the train without a ticket

The original sentence is natural and common, but it is slightly broader than a strict legal prohibition.

Yes. This is a very natural Hebrew word order:

• אני = I
• לא יכול = can’t
• לעלות על הרכבת = get on the train
• בלי כרטיס = without a ticket

So the sentence builds in a straightforward way: I + not able + to board the train + without a ticket

Hebrew word order can be flexible, but this version is standard and neutral.