When I worked on railway vehicles (bogies for passengers vehicles, more accurately), Nord locks (or equivalent clones) were standard on all structural joints.

When I worked on railway vehicles (bogies for passengers vehicles, more accurately), Nord locks (or equivalent clones) were standard on all structural joints. Especially on a prototype I'd recommend them. Prototypes are really expensive, a complete supply of Nord locks for your project is probably less than a single one-off CNC part. Note that Nord locks are specced to be single use. Not that I've never reused some on prototypes, but, well, I'd never do it on a life-critical joint that is meant to be taken apart often.