To solve this problem, we need to understand the relative motion of the trains and the bird. Let’s break it down step by step:

1. The first train is traveling from Town A to Town B at a constant speed of 60 km/h. We can calculate the time it takes for this train to reach Town B using the formula: Time = Distance / Speed Time = 450 km / 60 km/h = 7.5 hours

2. At the same time, the second train is traveling from Town B to Town A at a constant speed of 90 km/h. Since the two trains are moving towards each other, we can consider their combined speed: Combined Speed = Speed of Train A + Speed of Train B Combined Speed = 60 km/h + 90 km/h = 150 km/h

3. Now, we can calculate the time it takes for the two trains to meet by dividing the distance between Town A and Town B by their combined speed: Time = Distance / Combined Speed Time = 450 km / 150 km/h = 3 hours

4. The bird starts flying from Town A at the same time as the first train leaves and continues flying until the trains meet. Since the bird flies back and forth between the two trains, we need to calculate the total distance it covers. We can calculate this by multiplying the bird’s speed by the time it takes for the trains to meet: Distance = Speed × Time Distance = 120 km/h × 3 hours = 360 km

Therefore, the bird will have flown a total distance of 360 kilometers.

In summary, the bird will fly 360 kilometers while shuttling between the two trains until they meet.