So this is a very long shot, and can really only be done by Union Workshop themselves. But with the KiHa 40 Series coming as part of the Tadami Line, and with the 40 Series being the replacement for the Kiha 130 that came with the Hidaka Main Line, a reskin for the Kiha 40 for the Hidaka Main Line would be a nice addition to the game, even though modern running on the line doesn't go past Mukawa Station following the 2015 storm damage, and the line abandonment of everything past Mukawa for bus services in March of 2021....
The KiHa 40 that ran on the Hidaka Main Line was different to those that ran on the Tadami Line. The Hidaka Mainline used KiHa 40-350s, which were based on the KiHa 40-700s used by JR Hokkaido, rather than the KiHa 40-500s and KiHa 40-2000s that ran on the Tadami Line. There are many key visual differences between them, such as smaller windows on the 40-350s and the hand rail going across the door. Pictures to show the difference between the 4 mentioned variants: KiHa 40-500 (Tadami Line) KiHa 40-2000 (Tadami Line) KiHa 40-350 (Hidaka Main Line) KiHa 40-700 (JR Hokkaido)