On Midland Mainline, I happened to find this. They are diagrams of a train and looking closely at the bottom one, it looks like a Class 373 (e300) Eurostar. Now please don't get your hopes up because I may be wrong. What do you think it is? What does it mean? I wonder...
there is a whole thread on it here: https://forums.dovetailgames.com/threads/brand-new-mml-secrets.81269/
it also seems like they copied the image of the laptop from there as its the same, except this one is slightly cropped
