Union Pacific strives to be a leader in developing technology and conscientiously using resources to reduce our environmental impact. Railroads are the most environmentally responsible way to transport ground freight. Each year, Union Pacific helps customers eliminate an estimated 20 million, or more, metric tons of Greenhouse Gas (GHG) emissions by choosing Union Pacific over truck transportation for their shipping needs. We’ve achieved this by making sustainability a priority, developing new technologies and methods to improve fuel efficiency, reducing emissions and working smarter to minimize our environmental impact.

Fuel Conservation

Union Pacific improves its fuel efficiency through improvements in locomotive technology, engineer training, and employee involvement. The result: Since 2000, Union Pacific has achieved a 22% improvement in fuel efficiency. See our Building America Report for additional information.

Greenhouse Gas Emissions

The company actively works to reduce GHGs and regulated air emissions through reducing fuel and energy consumption. 

The U.S. Environmental Protection Agency (EPA) GHG evaluations recognized that freight railroads account for just 2% of U.S. GHG emissions from transportation. Cars, light trucks, and motorcycles combined produce nearly 60%, while trucking generates more than 20%. Locomotives account for nearly all our GHG emissions, and we have reduced those emissions by investing in more fuel-efficient locomotives, retrofitting older locomotives to be more environmentally friendly, and adopting more efficient operating practices.

Union Pacific improves its locomotive fuel efficiency through investments in technology, engineer training, and employee involvement. The result: Since 2000, Union Pacific achieved a 22% improvement in fuel efficiency, which appears to correlate with lower and less hazardous air emissions. Emissions inventory updates for our California yards confirm the air emission reductions in diesel particulates by roughly 70% since 2005.

Additionally, Union Pacific has ultra-low sulfur fuels since 2006 and biofuels since 2010. The GHG section of our Building America Report is available for review of specific GHG and non-GHG emissions information.

Rail is the most fuel-efficient way to move freight over land, and Union Pacific plays a valuable role in helping customers limit their carbon footprint.


We operate two primary types of locomotives – high-horsepower locomotives that pull freight over long distances and low-horsepower switch locomotives that work in train yards, sorting and delivering cars. We are committed to emissions reductions and are constantly conducting research to further reduce emissions.

Union Pacific works with locomotive manufacturers to develop technologies that meet or exceed EPA standards. Since 2009, Union Pacific has spent about $3.4 billion to purchase new, more fuel-efficient locomotives. Since that time, approximately 1,300 locomotives have been added to Union Pacific's fleet, and about 2,800 older locomotives were retired. See our Technology section to learn about Union Pacific’s pioneering locomotive initiatives.

There are five tiers of locomotive emission standards set by the EPA, which are progressively more stringent. These standards require continuing reductions in locomotive exhaust emissions of nitrogen oxide (NOx), particulate matter (PM), and other pollutants. The highest standards, called Tier 4, took effect in 2015 for newly-built locomotives that reflect the application of high-efficiency aftertreatment technology.  The EPA estimates this technology results in PM and NOx reductions of about 90% compared to older switch locomotives.

 Locomotive Idling and Operating Practices

Our employees commit to using techniques that eliminate unnecessary fuel consumption.

In a railroad operating environment, locomotive engines may be kept idling for several reasons:

  • In a yard, they idle between work events;
  • On the main line, they idle while meeting or passing other trains, and to maintain air brake pressure; and
  • In cold temperatures, they idle to keep their cooling system from freezing.

Union Pacific has a comprehensive plan to reduce the amount of time locomotive engines idle. Part of the plan involves using automatic stop-start equipment on newer locomotives to eliminate unnecessary idling. Older locomotives are being retrofitted with similar technology. Nearly 99% of Union Pacific's locomotive fleet is equipped with this technology. Locomotive shutdowns can save 15 to 24 gallons of fuel per locomotive, per day.

Operating practices that improve fuel efficiency and reduce fuel consumption include:

  • Managing train speeds and length to maximize miles per gallon;
  • Avoid stopping and maintain network fluidity; and
  • Integrating our network and interchange operations with those of other railroads to minimize delays and reduce locomotive emissions.

Rail Cars

How we manage rail cars has tremendous environmental value. Actions include:

  • Building a transportation plan to optimize performance, with initiatives such as maximizing train tonnage for the route structure and adjusting how we switch rail cars on trains to minimize blocked crossing time, which leads to reduced idle time for drivers in the communities we serve;
  • Using proprietary software to route cars with as few miles and handlings as possible;
  • Increasing carrying capacity; increased allowable weight and reduced tare weight from lighter materials have increased freight car carrying capacity by more than 25% since 1980, which reduces the number of cars and fuel required to move the same freight;
  • Working with participating North American railroads to create national pools of high quality freight cars with the same general characteristics, reducing empty miles and freight cars required to meet customer needs;
  • Upgrading refrigerated boxcars to reduce diesel particulate matter emissions;
  • Collaborating with shippers to increase car capabilities, improving integrity, and safety;
  • Extending the life of new rail cars from 40 years to 50+ years by improving design and construction;
  • Reusing parts when we scrap rail cars;
  • Reducing the wind resistance of intermodal trains by matching the rail car length with container length, and reducing the number of empty slots.

Resource Use

Union Pacific's sophisticated approach for managing waste follows three principles:

  • Minimizing resource requirements;
  • Divert waste from the landfill; and
  • Managing waste responsibly and in full compliance with regulations.

We evaluate the company's entire waste generation. The company typically generates about 1.4 million tons of waste annually and about 70% is recycled or repurposed. 

Used railroad crossties make up one of our largest waste streams. We use a sophisticated system to monitor our railroad tie replacement cycle to ensure ties are replaced only when end of life has been reached. Where possible, Union Pacific reuses railroad ties on our 32,000-mile network. Of the millions of wood railroad ties we replace annually, approximately 85% are recycled or repurposed.

Union Pacific uses concrete ties in high-tonnage, high-traffic areas, where wear and tear is greater. Concrete ties generally require fewer materials and generate less waste. We also use composite ties, made from 100% recycled plastic, in areas such as the Gulf Coast where wet weather reduces the lifespan of wood ties.

Our operation frequently requires moving soil to support our infrastructure. We employ a comprehensive soil testing process and re-use every ton possible.

We have worked to reduce paper consumption and implement changes to facility lighting, watering practices, and other resources. At locations that we provide water for employees, we minimize resource use where practical and have worked with other water suppliers to reduce the volume of plastic where we provide bottles.

In a typical year, Union Pacific recycles:

  • 400,000 pounds of electronic equipment;
  • One million pounds of signal batteries;
  • More than 250,000 tons of metal, the equivalent GHG emissions to power more than 125,000 homes for a year;
  • More than 4 million gallons of oil and diesel fuel, 100% of the oil captured at fueling and servicing facilities; and
  • More than 30,000 tons of solid waste, the equivalent GHG emissions as burning nearly 14,000 barrels of oil.

Union Pacific reduced the Resource Conservation and Recovery Act (RCRA) hazardous waste to 0.2% of total waste generated in a typical year. For waste with potential hazardous characteristics, we utilize trained, qualified third parties to oversee shipments from start to finish. This includes sampling, as needed, to properly characterize and dispose waste and managing logistics to meet regulatory timeframes.

We employ a comprehensive soil testing process and re-use program, work to reduce paper and plastic consumption, and utilize metal recycling bins. Additionally, we recycle locomotive parts, rail, tie plates, spikes, anchors, and rail car parts. Union Pacific scraps rail cars that have reached the end of their useful life. In many cases, scrappers strip useful parts from the cars, which are sold back to Union Pacific for continued use. The remaining metal can be re-purposed in the manufacturing of other metal components without drawing from other natural resources.

Union Pacific looks for re-use opportunities in the community for items. For instance, the company has provided used computers and monitors to those who don’t have access to them, including sending laptops to nonprofit organizations for use in developing countries.