title: Regulated and non-regulated emissions from in-use diesel-electric switching locomotives.
abstract: Diesel-electric locomotives are vital to the operation of freight railroads in the United States, and emissions from this source category have generated interest in recent years. They are also gaining attention as an important emission source under the larger set of nonroad sources, both from a regulated emissions and health effects standpoint. The present work analyzes regulated (NOx, PM, THC, CO) and non-regulated emissions from three in-use diesel-electric switching locomotives using standardized sampling and analytical techniques. The engines tested in this work were from 1950, 1960, and 1970 and showed a range of NOx and PM emissions. In general, non-regulated gaseous emissions showed a sharp increase as engines shifted from non-idle to idle operating modes. This is interesting from an emissions perspective since activity data shows that these locomotives spend around 60% of their time idling. In terms of polycyclicaromatic hydrocarbon (PAH) contributions, the dominance of naphthalene and its derivatives over the total PAH emissions was apparent, similar to observations for on-road diesel tractors. Among nonnaphthalenic species, itwas observed that lower molecular weight PAHs and n-alkanes dominated their respective compound classes. Regulated emissions from a newer technology engine used in a back-up generator (BUG) application were also compared againstthe present engines; it was determined that use of the newer engine may lower NOx and PM emissions by up to 30%. Another area of interest to regulators is better estimation of the marine engine inventory for port operations. Toward that end, a comparison of emissions from these engines with engine manufacturer data and the newer technology BUG engine was also performed for a marine duty cycle, another application where these engines are used typically with little modifications.
authors.affiliation: College of Engineering--Center for Environmental Research and Technology, and Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, California 92521, USA.
authors.forename: Aniket A
authors.initials: AA
authors.lastname: Sawant
authors.forename: Abhilash
authors.initials: A
authors.lastname: Nigam
authors.forename: J Wayne
authors.initials: JW
authors.lastname: Miller
authors.forename: Kent C
authors.initials: KC
authors.lastname: Johnson
authors.forename: David R
authors.initials: DR
authors.lastname: Cocker
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002248:Carbon Monoxide / Q000032:analysis; D004784:Environmental Monitoring; D005742:Gasoline / Q000032:analysis*; D018986:Motor Vehicles; D009589:Nitrogen Oxides / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D014481:United States; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D005742:Gasoline; D009589:Nitrogen Oxides; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions; D002248:Carbon Monoxide