To me the PDF link I provided almost reads like someone's Doctoral thesis, as do so many of the white paper style documents on most any subject we care to research.
This puts me in mind of studies in frequency canceling or augmenting generators incorporated in many sensitive instrument testing equipment. In the drive-line components of the automotive industry for instance particularly the universal or constant velocity joints it was discovered almost 100 years ago that the shafts could not only transmit vibrations but also at certain frequencies their rotational movements through the ever changing angles of the drive shaft would cause premature wear in the engines transmissions and differentials. through the years manufactures have experimented with everything from rubber inserts in the drive shafts to filling them with corrugated paper or using thicker smaller diameter shafts and thinner larger diameter shafts various sized "U" joints have been used even some vehicles used dissimilar sized joints even going so far as balancing the shafts to 5 times the maximum RPM they could ever spin, all in an effort to create longevity and near soundless operation.
Roller coaster rides share a common problem with trains they run on rails. Often these rails are parallel cylinders due to the rotational speed of the wheels on the rides a tremendous amount of sound waves are transmitted through the rails as everyone knows who has ever been to a amusement park the coasters are often the noisiest rides in the park even in the largest of parks the roaring swoosh sounds comping from them can be heard for great distances above any other ride in the park. various substances have been used to make the wheels out of, filling the rails with liquid or sand, paper or a host of other materials have been used in an effort to quieten these sounds. the coasters with the loudest noises often require the highest rail maintenance or even sectional replacements sometimes in areas where the least amount of lateral stresses are present.
I'll make a supposition that on trains at least some of the corrugation of the rails might possibly be lessened by careful placement of the rail cars with varying sized wheels.