Industrial natural gas engines are becoming increasingly popular in the oil and gas, marine and electric power industries due to the fuel savings and reduced emissions they offer. WPP sells a wide array of industrial gas engines, including Caterpillar natural gas engines such as the CAT G3516, G3412, G3406, G3306 and even the latest CAT CG137-12 and CG137-8 models. We also offer Waukesha 7042, 7044, and 9390 industrial gas engines fully rebuilt to manufacturer specifications.