Novelty 2025: After Poland's first mainline diesel locomotive, the SP45 series, had proved its worth, the Polish state railways decided to procure a more powerful version that could also be used in heavy, high-quality passenger train services. The innovations of the new PKP diesel locomotive also included electric train heating and the production-optimised shape of the drivers' cabs and the locomotive body with the corrugated side walls. After minor teething troubles with the prototype locomotives SU46-001 and SU46-002 had been recognised and cured, the Poznan locomotive construction company Cegielski delivered a further 50 SU46s from 1976 to 1977. Digital switching of drivers' cab lighting and engine room lighting by retrofitting a digital decoder | True-to-original lamps | Freestanding handlebars and windscreen wipers | Detailed roof design