In 1973 Pafawag built a prototype passenger locomotive of the building type 201Ea, which had a different gear ratio for top speed 160 km/h, with no other substantial changes. The locomotive was classified as EP23-001, being a sole machine of this class. After a series of tests, the locomotive characteristics were found unsatisfactory and no more were built. In 1979 the prototype was rebuilt to ET22 standard and renamed ET22-121 in place of former locomotive 121 scrapped in 1977. Today this locomotive is conserved in Jaworzyna Śląska railway museum.