Question 497457
Initial speed of ball=55mph---------------------speed of train

Final speed of ball=initial speed(55mph) + speed that it was pitched(55mph)=110mph for a brief period until it slows down.

Try dropping something eco-friendly out the window of a moving car and observe what it does.  It will head out in the direction the car is traveling, bouncing along the highway, at the same speed of the car for a brief instance.

Hope this helps-----ptaylor