<p>This study investigates the influence of friction block geometry, specifically the effect of different slot configurations, on the dynamic and contact behavior of high-speed train braking systems. Conventional slot designs, including single-slot, double-slot, and vertical-slot configurations, were compared with a pentagonal block containing a central hole. The analysis was conducted using numerical simulations in Abaqus, employing both Complex Eigenvalue Analysis (CEA) and Transient Dynamic Analysis (TDA) to evaluate vibration characteristics and friction-induced instabilities. Unlike most literature reviews focused on automotive brake pads or perforated friction blocks, this work provides an investigation of slot number and orientation in pentagonal friction blocks used in high-speed train braking system. In CEA, eigenvalues were extracted using the subspace projection method, while in TDA, system instability was examined through the explicit central difference integration method. The results indicate that replacing traditional slot designs with alternative configurations did not lead to coupling of vibration modes within the system. However, variations in disc rotational speed were found to significantly influence the diagonal contact angle between the friction block and the disc. An increase in speed caused a corresponding increase in contact inclination, accompanied by higher contact pressure. Among the tested configurations, the pentagonal block with a vertical slot exhibited the highest contact angle and pressure, resulting in incomplete surface contact and localized stress concentrations. These findings suggest that block geometry plays a critical role in vibration behavior, wear mechanisms, and overall stability of high-speed train braking systems. These findings may demonstrate that slot design plays a dual role by suppressing friction-induced mode coupling, while simultaneously altering contact behavior, providing new insights for optimizing high-speed train brake pad design.</p>