What is their effective minimum radius and how does their noise level compare with other Bowser locomotives? I am finishing a Big Boy that seems somewhat noisy even after recommended "fixes" such as making sure the universal is not "bottoming out" and checking the free play of the drivers. The curves it operates on are about 29" radius, although the track is not too smooth vertically (it goes up and down a litle). What kinds of experiences have people had with these locos?