I have some time those weeks to spend on OpenTTD and because I usually play in order not to get bored (challenge is not of my interest), I modified the Hover Bus GRF in order to have a overpowered vehicle, and on the same time to learn more of the YAGL translation (NML will be another part of fun further

Of course, this cheat vehicle is not intended for fair games...
So here is the FRV - Fastest Refitable Vehicle.
Based on the Hover Bus GRF code (credited in the GRF description, of course), I put at max its specifications of speed, cargo abilities, and other parameters (free costs for example). Only the passenger cargo amount is stuck at 255 because I still didn't find the way to callback the default "cargo_capacity" parameter).
Speed mechanics are quite interesting by testing many values and combinations... Never use a 0 ton weight in your GRF

TAR Archive created according to the syntax, and a unique GRF ID according to the Creators ID common rules, I took "AK", 414B in hex, never used as far as I searched or in the reserved fields. I'm a new member, don't want to make waves...
Have fun, people who want to go fast or cheat in their games!