Featured Application The presented results can be used in designing synchronous homopolar machines and railway undercar generators. The article presents the optimal design of a 35 kW brushless synchronous homopolar generator without permanent magnets for railway passenger cars. The excitation winding of the generator is located on the stator, and the toothed rotor has no windings. The generator characteristics are optimized considering the required constant power speed range. A single-objective Nelder-Mead algorithm and 2D Finite Element Analysis were used for the optimization. As a result of the optimization, power losses are significantly reduced over the entire operating range of the generator rotational speed, the current capacity of the solid-state rectifier, and the torque ripple. A comparison of the calculated characteristics of the generator under consideration with the characteristics of a commercially available undercar generator shows that the active volume is reduced by a factor of 2.1, and the losses are significantly reduced over the entire operating speed range.