Monitoring problems of torsional vibrations in shaft trains of turbo-generator sets at power plants are discussed, and demands on the control system design are analyzed as well. The structure charts of the monitoring systems built in existing turbo-generator sets and the first visualization results of natural torsional vibrations in the shaft train of the T-175/210-130 turbo-generator set at Omsk TPP 5 (thermal power plant -5) are provided. Experimental natural frequencies of the shaft train torsional vibrations are compared to their computed values.