I think the livery should have focused more on the rail red and the double arrow logo that defined British Rail. I decided to come up with a livery based on that, while also trying to make it easier for the depot people to maintain. I will try to text-describe the image.
The livery is predominantly red, with a white roof and lower half, and blue passenger doors (in line with page 49 of the wayfinding guidelines, located at
https://www.networkrail.co.uk/wp-content/uploads/2022/11/Wayfinding.pdf). The double arrow at front is white on a red background, without the "GBR" text.
The service logo is at the lower centre of the carriage on a white background, consisting of a red double arrow, and the region or service in black text. Provision is also made for the train name at the lower front, such as "Arterio" or "Azuma", either in plain white text on red background, or plain red text on a white background. Black on white was selected over blue on white, to reflect the wayfinding guidelines and for maximum contrast.
First class is indicated with a yellow upper band and quiet coaches have a sky blue upper band. On Intercity trains, the number 1 indicates first class, and the letter Q indicates a quiet coach.
Credits are as follows:
The image is licensed under CC-BY-SA 4.0.