The performance and detailed flow physics of a transonic, low-pressure turbine (LPT) stage with design Zw=1.35, ∆hT /U2 = 2.8, ϕ = 0.78, and η = 90.5% has been investigated experimentally. Recent developments in boundary layer transition modeling were utilized in the aerodynamic design of the stage. Measurements were acquired in a recently developed, high-speed turbine facility constructed to investigate the effects that Reynolds number, nozzle exit flow, freestream turbulence, vane-blade spacing, and rim seal flows have on the loss generating mechanisms of a highly loaded LPT stage. Flow control techniques were applied at the stage inlet with the intent of reducing a source of stage losses. A research dissertation designed to provide understanding of the loss mechanisms that reduce the effectiveness of the Notre Dame Highly Loaded Turbine Stage 01 (ND-HiLT01) is described.