I have a Williams Bachman 44 tonner that I bought about 8 months ago, and I run it on an MRC Z-1000 transformer, and the sounds are very loud. No problem there. And, it runs very fast and strong.
BUT, the coupler is so stiff that it will derail any car I put right behind it, unless I put alot of weight in that car.
It pulls the heavy car OK, BUT, if I back up the train around any curved section, the Williams coupler automatically comes open and loses the car. Don't know why. (The cars I put behind it are old school, all metal Lionel gondola cars or log cars.)
My only solution, is to turn off the E-Switch in the 44 tonner, so that it never backs up. :-(