This locomotive was the second conversion project by Engenious Engineering for the Class I railroad.
In 1987, a Class I railroad finished the development of new locomotive technology. An experimental engine conversion project had begun years prior, aiming to capitalize on the stable and cheaper cost of natural gas. The project was successful, but the infrastructure requirements to make it financially viable were too big to swallow.
Engenious Engineering (formerly Energy Conversion Inc.) was chosen to take on development. With a list of requirements in hand, an EMD 645E3 test engine was purchased, and development began on the first commercial dual-fuel conversion.
Work started by identifying key design areas, such as engine knock, air temperature, fuel mixing, and fuel timing. Efficiency and diesel-only backup mode were necessary for the railroad requirements.
Engine knock was the biggest concern and a weakness of the previous conversion design, with the engine derated 25% to prevent detonation. Power capacity in this new conversion was improved by redesigning the pistons to reduce compression ratio and promote cylinder mixing turbulence. This change resulted in improved air fuel mixing and more stable combustion.
Installation of a turbocharger wastegate and two aftercooler radiators allowed for improved fuel efficiency. This compensated for the additional air needed for dual-fuel combustion, allowing exhaust to escape more quickly and improving air temperatures, promoting better combustion.
The predecessor's gas inlet valves were cam-actuated, causing issues if the engine ran solely on diesel. A redesign used electric solenoid valves, allowing for safe operation in diesel-only mode and better gas injection control.
An engine control unit was designed to manage everything, complete with sensors. It sequences fuel timing and processes engine data along with external controls information. Switching to diesel-mode and operation of the new wastegate is also managed by the unit
After evaluation, the results were what EE thought possible: a fully rated dual-fuel conversion with substitution rates over 90%. Diesel operation was maintained, and thermal efficiency was similar to an unmodified engine.
The locomotive was put into service in late 1991 following FRA approval. A second conversion was applied by EE, designed as a retrofit kit solution that could be applied at scale across their fleet.
Since these projects, EE continues to develop conversion technology for when rail infrastructure is ready for it. Currently the technology is known to greatly reduce emissions, seeing use on EMD MP Gensets, stationary power, and backup generators worldwide.