After Oxford's personal airship was nixed from the script, I was asked to design a sumptuously appointed railway carriage for the trip to Russia. This would combine a study, lounge and bar, and was meant to evoke the style of the Kingsman tailor shop.
As it happens, I'm also an avid European model railroader, so this task was right up my alley. Much of the basic inspiration for the exterior came from the LNWR King Edward VII Saloon car and Queen Victoria's Royal Carriage, while the interior also references various custom Pullman coaches of the era. My single favorite rail coach is the observation car from the TEE (Trans Europe Express) Rheingold, and while that's a far more modern piece of rolling stock it inspired the central skylight. The color palette went through a few iterations, but was ultimately pulled from the Oxford Tartan, which is featured on the walls.
In the end though, even this was a little too fanciful for the tone director Matthew Vaughn was going for, so it was simplified into a much more conventional first-class coach.