This paper documents the initial test results of a locomotive diesel particulate filter (DPF) retrofit project. The locomotive used for this project was BNSF1284, a 1,566 kW National Railway Equipment Company (NREC) model 3GS21B, originally manufactured in April, 2008, and designed to be an Ultra-Low Emissions Locomotive (ULEL). This genset switcher locomotive uses three Cummins QSK19 Cummins 522 kW diesel-engine driven generator sets (Genset 1, 2, and 3) to provide the power needed to drive the traction motors.
The GT Exhaust Diesel Particulate Filter (DPF) retrofit system, installed on BNSF1284, uses catalyzed DPF elements. The DPF, and its catalyzed coating, offered significant hydrocarbons (HC), carbon monoxide (CO), and particulate (PM) emissions reduction. Additionally, the catalyzed coating should allow the diesel particulate filters to passively regenerate at moderate exhaust temperatures, thus keeping the engine back pressure within allowable limits of the manufacture.
The GT Exhaust DPF’s were installed in place of the standard mufflers on each of the three engines. The GT Exhaust DPF’s are roughly the same size as the stock muffler. The only locomotive modification needed to install the GT Exhaust DPF’s was to the muffler mounting platform, directly above the engine, where the exhaust pipe opening needed to be enlarged. There are no external modifications to the locomotive car body needed to install the GT Exhaust DPF’s.
After installation of the DPF’s, they were degreened by operating the engines at rated power for 20 hours. After degreening testing was performed according to Title 40 of the U. S. Code of Federal Regulations (CFR), Part 92, Subpart B. The addition of the DPF reduced the PM emissions to 0.016 g/kW-hr or 60 percent below the locomotive Tier 4 PM limits.
BNSF1284 was returned to revenue service in Richmond, California in March 2012, where the DPF performance will be tracked for 3,000 hours of operation as part of a California Air Resources Board (CARB) verification program.