G-volution and SBL-Rail present dual fuel evolution concepts for Class 37, Class 59 and Class 66 locomotives. Dual fuel engines use compression ignition and burn two fuels simultaneously. This work shows how diesel fuel can be replaced by renewable net-zero carbon emissions fuels. The original diesel tanks were replaced with smaller ones and cylinders for biomethane or biopropane or hydrogen were installed. Compared to the original two-stroke EMD engine, the new four-stroke dual-fuel engine has a 10% reduction in fuel consumption. If a Diesel Particulate Filter (DPF) is installed, the engine will spend less time responding to the increase in back pressure when the DPF fills. Route simulations were completed using OTMRs provided by these locomotive operators in combination with dual fuel engines. 

The Wärtsilä 46TS-DF engine is the company's latest multi-fuel engine that can run on LNG, reducing air pollution, while also providing a viable basis for future decarbonization through biological or synthetic methane. According to the technology company, the engine was developed with a focus on economy, environmental performance and fuel flexibility, ushering in a new era of medium-speed marine engines. In April 2021, the Chantiers de l'Atlantique shipyard received the first order of this engine type from Royal Caribbean Cruises. The engines will be installed on the company's newest Oasis-class ship, Ocean Utopia. The vessel is currently under construction and will feature six Wärtsilä 46TS-DF engines with gas valve units and NOx reducers.

Isobutanol was injected with the intake port at premixed energy ratios (PER) of 10%, 20% and 30%. Diesel, B20 and B100 are direct injection fuel. DFC reduces nitrogen oxide (NOx) emissions at moderate loads compared to CCM. Compared with CCM, the flue gas emissions of diesel DFC under rated load are reduced by 10.15%, 22.12% and 7.40%, respectively. At 30% PER, the exergy efficiency of the D FC for B20 increases by 0.91, 5.23, 3.65, 1.22, and 6.14% from 20% to 100% load, respectively.