It is a derivative of the Stadler FLIRT and began entering service in 2021.

BLS AG ordered 58 trainsets from Stadler Rail in 2017 at a cost of CHF 650 million.

[5] Each formation is composed of six cars, with a maximum seating capacity of 275.

Ten BLS RABe 528 are named after communes in the Swiss cantons of Bern, Lucerne and Neuchâtel, while two additional ones are named after communes in the Italian state of Piedmont.

Each train bears the commune's coat of arms (COA) below the driver's window.