The sentence “ট্রেনটি ঢাকা যাবে” expresses a fixed or scheduled action. When we say a train “will go” or “is going,” we usually talk about a plan or movement. But in English grammar and usage, when we refer to a train, bus, ship, or flight that has a fixed destination, we often use the phrase “is bound for” to show that it is going toward a certain place.

The phrase “is bound for” means “is going towards” or “is destined to reach.” This is a formal and correct expression for vehicles like trains, buses, or airplanes that have a definite route or direction.

Example:

• The ship is bound for Singapore.

• The flight is bound for London.

• The train is bound for Dhaka.

These examples show that the vehicle’s destination is certain. It’s not just moving; it is officially or naturally directed to that place.

Now let’s see why the other options are not perfect in this case.

The train is going to Dhaka — This sentence is grammatically correct but not as natural when describing public transport schedules. We use it in spoken English or casual talk.

The train is leaving for Dhaka — This means the train is about to start its journey. It focuses on the starting moment, not on the train’s destination itself. So it gives a slightly different meaning.

The train will go to Dhaka — This is simple future tense. It tells about a possible or planned action in the future. But it doesn’t sound natural for scheduled or regular trains, because trains run according to a timetable.

In standard English usage, especially in railway announcements, newspapers, or official timetables, the expression “is bound for” is most appropriate. It sounds formal, correct, and fits the meaning of “ঢাকা যাবে” perfectly.

In real usage:

• Correct: The train is bound for Dhaka.

• Incorrect or less natural: The train will go to Dhaka.

Therefore, the most suitable and idiomatic translation of “ট্রেনটি ঢাকা যাবে” is “The train is bound for Dhaka.”