Air Quality and Environmental Justice Lead to Push for Zero-Emission Locomotives

The California Air Resources Board has petitioned the U.S. EPA to adopt more stringent emissions standards for locomotives in order to improve air quality at rail yards, many of which are located adjacent to disadvantaged communities.

3 minute read

April 23, 2017, 7:00 AM PDT

By Irvin Dawid


"Reducing locomotive-related emissions and the resulting air toxic hot spots near railyards is a high priority for disadvantaged communities within California and around the nation,” said California Air Resources Board chair Mary D. Nichols in an April 14 press release.

Proposed emission standards would cut toxic and smog-causing emissions by 85% for diesel particulate matter (PM) and 66% for oxides of nitrogen (NOx) below current ‘Tier 4’ levels. Newly manufactured locomotives would have some zero-emission mile capability.

Courtesy of California Air Resources Board 

According to the internet forum DieselNet, Tier 0-2 standards, adopted in December 1997, were "applied to locomotives originally manufactured from 1973, any time they were manufactured or remanufactured."

Tier 3-4 standards: A regulation signed in March 2008 introduced more stringent emission requirements. 

  • Tier 3 standards became effective from 2011/12. 
  • Tier 4 standards, which were originally intended to require exhaust gas aftertreatment technologies, became effective from 2015. 
  • The 2008 regulation also includes more stringent emission standards for remanufactured Tier 0-2 locomotives.

"CARB is requesting the development of updated emission standards, including standards for newly manufactured locomotives as well as for remanufactured locomotive engines," writes Stuart Chirls for RailwayAge.

Nichols urged the [U.S. Environmental Protection Agency] EPA “to exercise its authority to adopt more stringent locomotive emission standards to address issues affecting public health and welfare, and so that all states can meet federal air quality standards and climate goals." The Board asked the EPA to respond by this summer.

However, already stringent Tier 4 standards and market conditions may cause rail manufacturers to oppose CARB's petition, suggests an April 2016 RailwayAge article, "Engines of change," by William C. Vantuono, Editor-in-Chief:

“Two years ago, every serviceable locomotive was reactivated,” noted Oliver Wyman’s Jason Kuehn at Rail Equipment Finance 2016. “Now, 15% or more of the road locomotive fleet is in storage. The price spread between natural gas and diesel has choked off interest in LNG and CNG-fueled locomotives.

And Tier 4 emissions levels are so strict that they’ve halted the virtuous cycle supporting locomotive replacement. We’ve gone from the perfect storm to a dead calm in two short years.”

A 117-page technical report, "Transitioning to a Zero or Near-Zero Emission Line-Haul Freight Rail System in California: Operational and Economic Considerations Rail Emission Reduction Program" (pdf) was prepared for CARB by the University of Illinois at Urbana-Champaign Rail Transportation and Engineering Center (RailTEC).

It was determined that the most likely implementation scenario for any of the above locomotive technologies within the South Coast [Air Basin] is operation of a captive fleet of new technology locomotives within the basin and conventional diesel-electric locomotives outside the basin.

Trains entering and exiting the basin must exchange new technology and conventional diesel-electric locomotives at a locomotive exchange point facility near the boundary of the air basin. 

Tuesday, April 18, 2017 in RailwayAge

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Aerial view of town of Wailuku in Maui, Hawaii with mountains in background against cloudy sunset sky.

Maui's Vacation Rental Debate Turns Ugly

Verbal attacks, misinformation campaigns and fistfights plague a high-stakes debate to convert thousands of vacation rentals into long-term housing.

July 1, 2025 - Honolulu Civil Beat

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

July 9, 2025 - Diana Ionescu

Map of Haussmann's redesign of Paris in the 1850s through 1870s under Napoleon III.

In Urban Planning, AI Prompting Could be the New Design Thinking

Creativity has long been key to great urban design. What if we see AI as our new creative partner?

June 30, 2025 - Tom Sanchez

View of dense apartment buildings on Seattle waterfront with high-rise buildings in background.

King County Supportive Housing Program Offers Hope for Unhoused Residents

The county is taking a ‘Housing First’ approach that prioritizes getting people into housing, then offering wraparound supportive services.

July 11 - Real Change

Aerial view of suburban housing near Las Vegas, Nevada.

Researchers Use AI to Get Clearer Picture of US Housing

Analysts are using artificial intelligence to supercharge their research by allowing them to comb through data faster. Though these AI tools can be error prone, they save time and housing researchers are optimistic about the future.

July 11 - Shelterforce Magazine

Green bike share bikes parked in a row on a commercial street with outdoor dining and greenery.

Making Shared Micromobility More Inclusive

Cities and shared mobility system operators can do more to include people with disabilities in planning and operations, per a new report.

July 11 - Cities Today