At Zion Foodtrucks in the US state of Colorado, American-made steel and aluminium are combined with globally sourced stoves, refrigerators, vents and titanium piping to transform everyday vehicles into mobile restaurants. But instead of benefiting from Donald Trump’s push to revive US manufacturing, the company says it has been squeezed by higher costs and tougher competition. Since taking office, the US president’s import taxes on steel and aluminium have hit 50 per cent tied to his “beautiful”...