The Cummins X15N natural gas engine is being featured in new fuel systems and trucks, potentially bringing natural gas back into consideration for class 8 trucking. Some major fleets, including Walmart and UPS, are exploring the use of renewable natural gas (RNG) for cleaner operations. The development and deployment of RNG and related technologies, such as CNG systems from Hexagon Agility, appear to be gaining interest from fleets and manufacturers.