As we design and build our slightly off kilter cartoon worlds we can't forget about the real world. While we can make anything work in a concept drawing the truth is that people from the real world have to interact with the things we build. The trick is to keep those wonderful proportions and curved lines intact as we do it.
In the case of the rail inspection vehicle I am designing there are plenty of constraining elements that fight with the design intent. Real full size people need to fit relatively comfortably inside the cab. The rail gauge (distance between the rails) doesn't change. When dollars are a factor the off-the-shelf components are a whole lot less costly than custom made stuff. The train car of course needs to fit through existing tunnels and doorways. And the mechanical components and controls need to be all tucked safely inside and yet still be readily accessible for servicing. And the one concern that trumps everything is the center of gravity of the vehicle. Inevitably some compromises must be made.
But of course with plenty of creative thinking and lots of measuring, sketching, erasing, redrawing and juggling everything can work - without giving away too much of what we set out to achieve at the start. This is the fun and challenge of design.