Two topics are presented in this paper. First, results of train performance integrations that show how train running times on the Northeast Corridor route would be affected by progressive increases in maximum speed up to 210 mph and by progressive increases in curve speed limits up to the corresponding tangent track maximums are presented. The results show that, for the curves that exist on the Northeast Corridor, full benefit can be derived from the high maximum speeds offered by available technology only if curve speed limits are raised along with maximum speed. Second, two approaches for achieving increased speeds on existing curves are considered. One is the well-known approach of operating tilting body vehicles on track with moderately increased superelevation. The other approach is to operate nontilting vehicles on track with dramatically increased rail superelevation. It is noted in this paper that this latter approach not only offers substantial advantages but also presents substantial problems. Methods of overcoming these problems are suggested.