(A) : Two similar trains are moving along the equatorial line with the same speed but in opposite direction. They will exert equal pressure on the rails.
(R) : In uniform circular motion the magnitude and direction of acceleration remains constant but the direction of motion continuously changes.

In uniform circular motion, the direction of motion continuously changes which changes the direction of velocity and acceleration.

Due to rotation of earth, the centrifugal force acting on the trains will be different, but the weight of the trains is same. Hence, they will exert unequal pressure on the rails.