It shows up on this band because it shows contrast well. While roads tend to wind and curve a bit more rails seem to run in a straight line. The only difference i can tell is the difference between agricultural vegetation and non agricultural vegetation because of the patterns mentioned above. Concrete and bare soil seem to hiave the highest spectral reflectance.
Water is the easiest with concrete as runner up.
Yes, the contrast between features is enhanced. While some contrasts are enhanced, as mentioned before, other are made more difficult to tell apart and blurry.