Radius = 1500 m.
Train speed at rate of 66km/hr = 18.33 m/s
Therefore, Distance covered in 1 second = 18.33 m
Distance covered in 10 second = 18.33 × 10 = 183.33m
We know that θ = Distance / radius
θ = 183.33 / 1500
= 0.122 radian
Therefore θ = 0.122 x 180/π = 7°