Abbott to Participate in PHH GreenFleet; Hybrid Pilot Wraps Up This Year
EEStor Announces Two Key Production Milestones; 15 kWh EESU on Track for 2007

Union Pacific Testing Railroad Industry’s First Exhaust Catalyst in Los Angeles

Catalyst panels are housed in the V-shaped cradle running the length of the manifold. Also see diagram below. Click to enlarge.

Union Pacific is beginning a year-long field test in the Los Angeles area of the rail industry’s first long-haul diesel electric locomotive modified with aftermarket experimental technology aimed at reducing exhaust emissions.

An experimental oxidation catalyst filtering canister (oxicat) manufactured by MIRATECH was installed inside the exhaust manifold of the 1992 SD60M locomotive’s 3,800 hp diesel engine. The catalytic material chemically reduces the amount of unburned hydrocarbons, carbon monoxide and particulate matter generated by the diesel engine, much like a catalytic converter on cars and trucks.


Click to enlarge.

The diesel engine has been outfitted with various sensors that can be remotely monitored with Global Positioning Satellite (GPS) technology. Remote realtime motoring capabilities help researchers evaluate how the experimental oxidation catalyst is functioning. Its emissions performance and the maintenance requirements for the locomotive will be assessed at the end of the one-year test period.

The locomotive was subjected to EPA locomotive standards testing before and after the installation of the oxicat using both standard EPA locomotive certification fuel and ultra-low sulfur diesel (ULSD) fuel that UP is now using for intrastate locomotives in California.

Static test results were:

  • Using ULSD fuel without the oxidation catalyst installed dropped particulate emissions by about 4% compared to the use of standard EPA diesel fuel.

  • Using ULSD fuel with the oxidation catalyst installed reduced particulate emissions by approximately 50%, unburned hydrocarbons by 38% and carbon monoxide by 82%.

During this initial testing, the 17-year-old locomotive met the latest EPA Tier 2 new locomotive requirements for particulate matter. The EPA’s Tier 2 requirements are for new locomotives manufactured since January 1, 2005.

Union Pacific has also begun a year-long field test in Oakland of the North America rail industry’s first experimental after-market exhaust system filter to determine if it will reduce diesel engine emissions in older locomotives used in rail yards. (Earlier post.)

The National Vehicle Fuels and Emissions Laboratory (NVFEL) of the US Environmental Protection Agency (EPA) based in Ann Arbor, Michigan, is funding most of the oxidation catalyst test.

Currently, about 50% of Union Pacific’s more than 8,200-unit locomotive fleet is certified under existing EPA Tier 0, Tier 1 or Tier 2 regulations governing air emissions. Union Pacific has tested, and is acquiring, two types of more environmentally friendly low-horsepower rail yard locomotives from Railpower:

  • The Genset locomotive is powered by three 700-horsepower low-emissions EPA non-road Tier 3-certified diesel engines projected to reduce emissions of both nitrous oxides and particulate matter by up to 80 percent, while using as much as 16 percent less fuel compared to current low-horsepower locomotives.

  • The Green Goat uses state-of-the-art diesel-battery hybrid-technology designed to cut air emissions by 80% and reduce diesel fuel use by 16% compared to conventional diesel-powered locomotives used in switching service. The hybrid switcher is powered with large banks of batteries. When energy stored in the batteries is depleted to a pre-set level, a small, low-emission diesel engine automatically starts to power a generator that recharges the batteries.



Rafael Seidl

Other than issues related to scale and longevity, the application of exhaust gas aftertreatment technology in large diesel engines (gensets, railroad & marine) is complicated by the fuel and engine oil qualities used. A particular problem is sulphur content, which can range from 300 to 3000ppm. Another serious complication is that older drivetrain designs have to be retrofitted rather than replaced. Using ULSD with 15ppm sulphur, as is done in this trial, increases unit fuel costs for the operator.

Note that reliable oxidation catalysts are a prerequisite for any future application of SCR technology to eliminate excess NOx.

Note also that in diesel engines that are operated near full load most of the time, continuously regenerating traps (CRTs) rather than wall-flow DPFs are used.

On a related note, it is possible (though quite a bit more expensive) to operate suitably modified heavy-duty diesel engines using natural gas. In the case of locomotives, this would have to be transported in a cryotank at around -160 deg C, admittedly a potential accident hazard. MAN recently presented a new ignition technology for large NG engines. A prechamber with a high-pressure gas injector and a glow plug is used. I permits the reliable ignition of even very lean mixtures with lambda > 2, such that the turbochargers are better utilized in part load. The design eliminates the wear and tear problems presented by spark plugs.


I just came back from a cruise and the diesel smoke could be seen for miles. one of the crew informed me the ship runs 365 days a year 24 hours a day (not including stopping at those little silly islands that you have to be back on at 4)and while reading this article it came to me that this catalst has many posibilties

shaun mann

big diesels are a big problem with comparatively cheap solutions.

GM understands this. That is why they started their clean transport tech from the bus end. A 1 mpg improvement in fuel effiency of a bus is much more valuable to the environment than a 30 mpg improvment of a civic. And big old engines can have their emissions reduced much more cheaply than already 95% optimised little engines.

Basically, Priuses are good for marketing, while better cats on busses, trains, and boats are good for the environment.


Aftertreatment devices, such as this one, does not work well on old engines. Old diesels emit overwhelmingly high amount of PM and lubrication oil mist, which clog aftertreatment filters in very short time. Probably, there is no way but complete re-powering of old locomotives to get them clean.

tom deplume

Locomotives could easily be adapted to use anhydrous ammonia (NH3)as fuel. NH3 is already produced in large quantities and burning it in locos is a better use than poisoning farmland. The tank cars are already present in large numbers and safe handling techniques well established. Use of a non-carbon fuel means there is no PM created and no CO2 as well. A small amount of ammonia could be injected into a SCR to eliminate all NOx. If use of renewable energy for electrolysis it would result in a rail system with zero CO2 emmissions.

The comments to this entry are closed.