CSX Advances Locomotive Technology to Cut Fuel Use and Emissions

Published: February 19, 2026

February 16, 2026 – Jacksonville, FL — CSX highlighted major progress on its ongoing efforts to reduce fuel consumption, cut greenhouse-gas emissions, and improve operational efficiency across its freight rail network through advanced locomotive technology.

The railroad is expanding deployment of its Automatic Engine Stop-Start (AESS) system — a platform that automatically shuts down locomotive engines when idle and restarts them when work resumes — significantly reducing unnecessary fuel burn and lowering emissions during idle periods. This system is a core part of CSX’s sustainability strategy and broader commitment to lowering operating costs and environmental impact.

CSX freight I136 is along the Wills Creek between Hyndman and Fairhope, Pennyslvania rolling east and downgrade around 2:15pm on October 17, 2024. Jon Wright photo.

Introduced in 2024, the upgraded AESS Assist adds enhanced shutdown performance and stronger battery support during engine starts, which improves fuel efficiency and is expected to help extend battery life. CSX says the added battery assistance reduces wear on starter systems and improves reliability.

CSX has also collaborated with locomotive supplier Wabtec Corporation to implement software optimizations on the AESS platform that allow engines to remain shut down longer without idling. These improvements further reduce fuel use and emissions — particularly in yard and terminal operations where idling has historically contributed to excess consumption and emissions.

While CSX has not yet announced specific system-wide fuel-savings figures for the current AESS rollout, industry analyses indicate that automated stop-start systems can cut idling fuel use by a substantial percentage — with commensurate reductions in carbon dioxide and particulate emissions — depending on operating conditions.

The AESS enhancements follow significant investment by CSX in locomotive fuel efficiency in recent years. The railroad has invested billions of dollars over the last decade in technologies, practices, and equipment aimed at lowering fuel use and emissions, helping its trains move roughly 528 revenue ton-miles per gallon of diesel fuel — a key rail performance metric — reflecting ongoing efficiency gains.

Earlier this month, CSX also announced a $670 million fleet modernization agreement with Wabtec — separate but complementary to AESS improvements — that will add 100 new Evolution Series locomotives and modernize 50 existing locomotives with advanced control systems designed to further improve fuel economy and reliability. Those upgrades include digital fuel-optimization features such as Trip Optimizer software, which has a track history of delivering measurable fuel savings on Class I railroads.

CSX says reduced fuel consumption not only lowers operating costs but also supports environmental and sustainability goals, consistent with broader industry trends toward cleaner operations. Railroads already move freight far more efficiently than highway trucks — with significantly lower carbon emissions per ton-mile — and incremental technology improvements like AESS build on those fundamental efficiencies.

“Enhancing locomotive efficiency is good for the environment and good for our customers,” CSX said in its announcement, emphasizing that technologies such as AESS help align operational performance with community and regulatory expectations around emissions and climate impact.

What’s next: CSX plans to continue monitoring performance data from AESS deployments and pursue additional retrofits and digital upgrades where they can deliver measurable fuel and emissions benefits. As the rail industry continues to innovate — including efforts around battery-electric and zero-emission locomotive technologies — incremental improvements like those CSX is implementing play a significant role in near-term decarbonization pathways.