This paper details part two of the demonstration of a 2,240 kW (3,005 HP) PR30C-LE locomotive with exhaust aftertreatment containing diesel oxidation catalysts (DOC) and urea-based selective catalytic reduction (SCR). The PR30C-LE is a remanufactured and repowered, six-axle, diesel-electric, line-haul locomotive. Program objectives were to measure emission levels of the locomotive and record locomotive and aftertreatment operations during a 12 month revenue service field trial. Phase 1 of the program involved engine baseline emissions testing as well as emissions testing with the aftertreatment at the beginning of its useful life, or the 0-hour condition. Results from Phase 1 showed engine-out emission levels were within U.S. EPA Locomotive Tier 2 limits. With aftertreatment at beginning of useful life, hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) were below Tier 4 limits, and particulate matter (PM) was below Tier 3 limits.
Phase 2 consisted of a 12 month revenue service field trial and additional emissions testing completed at the midpoint and end of the field trial. On-board GPS data, aftertreatment NOx sensor data, and various locomotive operating parameters were logged continuously during the field trial. The field trial data suggests the impact SCR technology has on locomotive NOx emissions is driven primarily by locomotive utilization and loading factor. Overall the field trial included 3,082 hours of operation and PRLX3004 generated approximately 572 MW-hours of work over the 12 month period. Emission test results at the 1,500-hour and 3,000-hour conditions showed very little change from 0-hour test results. Emission levels remained below Tier 4 limits for HC, CO, and NOx, and below the Tier 3 limit for PM. Phase 2 test results suggest there was no significant degradation in emissions performance during the field trial, and no major issues with the locomotive and aftertreatment were detected. In total there are currently five PR30C-LE locomotives in operation within California and Arizona. Together they have completed a cumulative 30,800 hours of revenue service through June 2012 without report of a major issue.