How did Richard Trevithick’s high-pressure engines differ from Watt’s engines?

James Watt’s engines were low-pressure designs, as Watt believed that using high-pressure steam was too dangerous. In contrast, Richard Trevithick successfully harnessed high-pressure steam, which allowed for significant differences in engine construction and application.123

Key differences include:

• Size and Weight: By utilizing high-pressure steam and allowing it to expand within the cylinder, Trevithick could build engines that were much smaller and lighter than Watt’s low-pressure models while maintaining equal power.1
• Portability: Trevithick’s engines were compact enough to be transported by ordinary farm wagons, whereas Watt’s engines were typically large, stationary installations.13
• Application: Because of their compact size, Trevithick’s engines were suitable for mobile uses, such as the world’s first steam railway locomotive and steam carriages, as well as powering portable machinery like threshing machines.12
• Efficiency: Trevithick’s designs, particularly the Cornish pumping engine, were significantly more economical than the Watt type, which they eventually replaced in mining operations.1