JR Freight will build new EF510-300 series electric locomotives to replace its current fleet of JNR Era ED76 and EF81 electric locomotives stationed in its Moji Yard in Kyushu. The main difference between it and the other models is that it will feature AC regenerative-braking and will be silver colored as a homage to its EF81-300 locomotives, which has an unpainted stainless steel body to prevent corrosion from operating in high humidity conditions inside the Kanmon Tunnel. The first production locomotive will roll out in December 2021 and they will formally enter service in March 2023
https://www.jrfreight.co.jp/storage/upload/08c9a4240c5fbab9404997b3ffc5e00f.pdf 