Wheel flats are known to cause high magnitude impact loads at the wheel-rail interface, which can induce fatigue damage and failure of various vehicle and track components. With demands for increased load and speed, the issue of wheel flats and a strategy for in-time maintenance and replacement of defective wheels has become an important concern for heavy haul operators. In this book, a validated model is utilized to investigate the characteristics of impact forces due to wheel flats and its effect on motions and forces transmitted to vehicle and track components. The results are analyzed to examine the sequence of events as the wheel flat enters into the contact area. The magnitudes and predominant frequencies of wheel-rail contact forces are examined in terms of system and operating parameters. A comprehensive parametric study is performed to analyze the effects of selected vehicle-track design and operating parameters on the wheel-rail impact loads, and forces transmitted to the bearing, railpad and ballast in the presence of single and multiple wheel flats within either same or adjacent wheels.