Historically, diesel locomotives have undergone countless facelifts. While sticking with the same primary color for its locomotives—Armour Yellow, or DuPont 88-1743—one railroad has by turns painted the top of its locos’ noses a flat dark-green, to reduce driver glare; adopted reflective unit numbers and silver skirts, or “trucks,” to improve visibility; and tinkered with the color brown here and there, just because.
Today, however, locomotives are undergoing changes that are virtually unseen if much more consequential—changes to what makes them run that have implications not only for railroad companies’ bottom lines but also for the health of their workers.
America’s railroads, which burn billions of gallons of diesel fuel annually amid growing pressure to reduce greenhouse-gas emissions, now are converting locomotives to run on liquified or compressed natural gas as well as diesel. The industry also has begun powering some locomotives with stored electrical power. Such changes would save money, maybe a lot. They also would strengthen the railroad industry’s advantage over long-haul trucks, industry observers say.
But one question remains, a question whose answer is likely to fully reveal itself only with the passage of time: Would changes to the way locomotives are powered improve the lot not only of railroads but also railroad workers, many of whom have fallen sick or died over the years from exposure to diesel fuel exhaust and its particulates or the coal that steam locomotives burned?
An eye-opening presentation
Occupational exposure to inhalable carcinogens has long been a significant cancer risk among railroad personnel. A 38-year study of workers exposed to locomotive diesel exhaust and its particulates attributed 4,351 deaths to lung cancer. Studies also have linked the use of diesel fuel to bladder cancer, esophageal cancer, laryngeal cancer, throat cancer, colon cancer, kidney cancer, and stomach cancer. The World Health Organization classifies diesel particulate as a known carcinogen whose inhalation is associated with increased risk of multiple types of cancer.
The link between diesel fuel and lung cancer has been known for a long time. In 1955, the lawyer Robert Straub, who then was employed by the Chesapeake and Ohio Railways Company, gave a presentation at a meeting of railroad claims executives titled “Potential Dangers from Exposure to Diesel Locomotive Exhaust.”
The risks to railroad workers’ health didn’t begin with diesel fuel, however. The coal that steam locomotives burned proved toxic for those in the engine room and others who inhaled it. Though the World Health Organization in 1997 found no conclusive link between coal dust and cancer, it has been found to cause other types of lung disease. And the cadmium in some coal dust has been found to contribute to the risk of lung and nasal cancer.
It wasn’t concern for the wellbeing of workers that was the primary driver of railroads’ move to diesel fuel, however. Steam engines used an inordinate amount of energy to build up steam pressure. In every week of operation, a locomotive consumed its own weight in coal and water. Only about one-twentieth, or five percent, of the potential energy in what a steam locomotive eats goes to the wheels as effective driving power. By comparison, a gasoline engine can deliver many times that potential energy.
Diesel engines, according to their designers, run faster and work longer than steam locomotives. They’re more fuel-efficient. They don’t require frequent stops to replenish coal and water. Instead of generating steam in an enormous boiler, the diesel engine burned oil to power a generator that, in turn, powered electric motors on the wheels.
The good and the bad
Overall, diesel engines have substantial economic advantages over other power sources for locomotives, according to dieselforum.org. They function with similar efficiencies as electric locomotives but do not require the capital investments in substations and electric distribution networks.
But diesel, like coal before it, came with health risks. Short-term exposure to high concentrations of diesel exhaust and its particulate matter can cause headache, dizziness, and irritation of the eyes, nose, and throat, according to OSHA. Prolonged exposure can increase the risk of cardiovascular, cardiopulmonary and respiratory disease, and lung cancer.
These health concerns primarily affect railroad workers. One of the first cases to result in a jury verdict in favor of a railroad worker was recorded in Georgia in 1999. The man at the center of the case worked as a railroad engineer for 18 years and died of naso-pharyngeal cancer, which forms inside the mouth. His surviving wife sued Norfolk Southern, alleging the company required her husband to be exposed to diesel exhaust for long periods of time.
The lawsuit also alleged that Norfolk Southern violated the Locomotive Inspection Act, which dictates that diesel exhaust was to be kept outside of the cab where her husband worked.
Breathing in diesel fumes for six days a week, four to 12 hours a day caused his cancer, a jury decided.
The height and location of many locomotive smoke stacks have allowed engine exhaust to flow into locomotive cabs. With the older configurations, engines had a long hood with the exhaust stack in front of the engineer’s cab. When the train moved forward, the diesel exhaust would float back toward the engine cab’s open windows.
Diesel fumes and exhaust can also affect people living near railroad stations; such proximity has been linked to an increase in cancer, according to a California study. While diesel-powered locomotives are more energy efficient than automobiles, they adversely affect the environment though the production of carbon dioxide, nitrogen dioxide, and particulate matter that pollute the air.
Seeking something better
Now here comes natural gas. What is it, exactly, and will it prove to be an improvement to the wellbeing of worker as well as the bottom line of railroads?
Liquefied natural gas is a colorless and odorless refrigerated liquid derived from natural gas, according to Philadelphia Gas Works. It consists primarily of methane and ethane.
This cold gas may freeze water vapor in the air, creating a visible white cloud. The cloud is useful for determining wind direction and product dispersion but does not define the boundary of the combustible gas; combustible vapors may exist outside of the visible cloud.
For railroads, liquified natural gas might ultimately prove to be yet another mixed bag of the good and the not-so-good. A 2019 alternative-fuel study that an engineering firm conducted for Chicago’s suburban commuter rail line, Metra, found the following:
- Natural gas is as much as $2-per-gallon cheaper than diesel.
- Facilities modifications, as well as the processing equipment required to compress the density of gas so it can be stored onboard, necessitate up-front capital expenditures.
- Locomotive conversions to accommodate the use of natural gas require a separate rail car, or tender, for storage, which may not be compatible with many existing operations.
- Onboard storage is a challenge even when the gas is compressed, given the limited space available within the locomotive.
Then there are the potential health effects of liquified natural gas. Breathing its vapors in large quantities may cause central nervous system depression with nausea, headache, dizziness, vomiting, and incoordination experts say.
Liquified natural gas and its vapor are asphyxiants that may cause loss of consciousness, serious injury, or death by displacing air, resulting in insufficient oxygen, especially in a confined space.
‘Consequences still unclear’
Another new if still largely experimental source of power for trains is electricity stored in batteries.
In a just-completed test, a freight train ran between two California towns with an experimental battery locomotive and two diesel locomotives, achieving a roughly 10 percent reduction in fuel consumption, “along with similar reductions in emissions of nitrogen oxides, small particulates and greenhouse gases,” according to the Los Angeles Times.
But there’s uncertainty about the effects of exposure to electro-magnetic radiation, too. Though no tests have been done to those working around or driving electric trains, a study by Scripps Clinic Research Foundation showed that high levels of EMF radiation can make drivers of electric cars drowsy. In addition, exposure to radiation while driving can result in headaches, neck stiffness, and dry eyes or blurred vision. And long-term exposure could have long-term health complications.
According to a 2016 study, “the consequences of low‐frequency EMF exposure are still unclear.”
“Health effects caused by long‐term exposure (such as cancer or neurodegenerative disorders) are mentioned in the literature, although conclusive results have not been obtained. Many long‐term studies have been described as questionable and of low repeatability,” according to the study.
“Moreover, it could be argued that long‐term effects are impossible to determine with certainty, since they take years or even decades to appear. Hence, long‐term consequences are a source of discussion within the scientific community.”
Which is to say that whether trains, figuratively speaking, are headed in the right direction with their evolving changes remains to be seen.
“The natural gas locomotives are relatively new and are still being studied,” Doran & Murphy partner Colleen Blinkoff says.
“I think the hope is that they will be safer for the crews and the general public, which would be great.”