Explanation:

- The train is 200 meters long.

- The speed of the train is 36 km/h, which is equivalent to 10 meters per second (since 1 km/h = $\frac{5}{18}$ m/s).

- The train takes 55 seconds to cross the bridge completely.

- In 55 seconds at 10 m/s, the train covers $10\text{m/s}\times 55\text{seconds}=550\text{meters}$.

- This 550 meters is the combined length of the train and the bridge.

- Subtract the length of the train from the total distance: $550\text{ m}-200\text{ m}=350\text{ m}$.

- Therefore, the length of the bridge is 350 meters.

Answer: 350 m