federal register - U.S. Government Printing Office

6392 Federal Register / Vol. 62, No. 28 / Tuesday, February 11, 1997 / Proposed Rulesmodes, expressed as a percent of thelocomotive’s rated power (e.g., 0.2% atidle and 1.0% at dynamic brake), andnot requiring that it be measured. Theseassigned levels, rather than measuredlevels, would be used in the emissionscalculations. This approach wouldalleviate concerns expressed by industryabout the ability to accurately measureengine power output during idle anddynamic brake operation. This wouldalso provide a regulatory incentive toreduce fuel consumption in these twomodes since the engine power used inthe calculations for these modes wouldalways be the same. This would in turnreduce total mass emissions. EPArequests comment on all aspects of thisoption, including what levels would beappropriate for the assigned powerlevels. The Agency also requestscomments as to whether a similarapproach should be used to provide anincentive for the development of anautomatic shutdown mechanism thatcould shut off an engine automaticallyafter some extended period of idling.One such approach would be to reducethe weighting factor for the idleemission rate, for engines equippedwith automatic shutdown mechanisms,but use the higher power weightingfactor that is specified in the proposedregulations. This approach wouldaccount for the emissions benefits of ashutdown mechanism whereas theproposed test procedures do not.EPA is proposing that test conditionssuch as ambient test temperature andpressure be fully representative of inuseconditions. Specifically, the Agencyis proposing that locomotives complywith emissions standards when tested attemperatures from 45° F to 105° F andat both sea level and high altitudeconditions (i.e., up to 7,000 feet abovesea level). The Agency is not proposingthat the test conditions includetemperatures below 45° F because theAgency does not believe that there aresignificant benefits from such arequirement for diesel locomotives ascompared to the benefits fromcontrolling cold temperature emissionsfrom gasoline-fueled vehicles (whereEPA does currently have coldtemperature requirements) since dieselengines are not associated with lowtemperature emissions problems.The Agency is not proposing specificcorrection factors that would be used toaccount for the effects of ambient testconditions, such as temperature orhumidity, on emission rates. In existingmobile source programs, EPA doesrequire that NO X emission rates becorrected to account for the effect ofambient humidity. (Water present in theintake air is known to lead to lower NO Xemissions, as it absorbs energy from thecombustion process and decreases peakcombustion temperatures.) EPAconsidered using the NO X-humiditycorrection factor that is currently beingused for highway and general nonroaddiesel engines (40 CFR parts 86 and 89),but concluded that the data upon whichthat correction factor was based is notadequate for this rulemaking. Inparticular, EPA has concerns about theapplicability of data from older precontrolhighway engines to current andfuture locomotives that incorporateNO X-reduction technologies. Moreimportantly, however, the data isinappropriate as a basis for suchcorrection factors for locomotivesbecause the range of test conditionsbeing proposed for locomotives is muchbroader than was used in the collectionof that data. EPA is in the process ofdeveloping revised correction factors forinclusion in the final rule and will placeany relevant information in the docketas soon as it is available. These wouldbe used to correct emission rates totypical ambient summer conditions of86 °F and 60 grains of water per poundof dry air. EPA requests comments onthe need for any correction factors,especially a NO X correction factor, andwhether proposed the conditions towhich emissions would be corrected areappropriate. Commenters supporting theuse of correction factors are encouragedto include test data that could be usedto develop meaningful correction factorsfor future locomotives.The Agency is proposing test fuelspecifications for compliance testing(certification, PLT and manufacturer/remanufacturer in-use testing) which areconsistent with test fuel specificationsfor on-highway heavy-duty enginecertification testing, with the exceptionof the sulfur specification. In the case ofthe sulfur specification, EPA isproposing a lower limit of 0.3 weightpercent, 17 and is proposing that there beno upper bound for the sulfur level.This lower limit is intended toapproximate worst case in-useconditions; in those cases where in-uselocomotives are operated on low sulfuron-highway fuel, particulate emissionsentering the atmosphere can beexpected to be lower than levelsmeasured when using the certificationtest fuel. EPA is taking this approachbecause there is no reason to believethat in-use locomotives will use onlylow sulfur on-highway fuel, especiallygiven the potential price differencesbetween low and high sulfur diesel17 Typical untreated (high sulfur) nonroad dieselfuel contains about 0.2–0.5 weight percent sulfur.fuels, and potential availabilityproblems in some areas of the country.Since the proposed test for therailroad in-use testing program is notthe proposed FTP, and railroad in-usetesting carries no liability with it, thereis less of a need to use the fuel specifiedfor certification for this railroad in-usetesting. Given the cost andinconvenience of using a specific fuelfor in-use testing, EPA is not proposingany fuel specifications for in-userailroad testing, and will allow therailroad testing to be done whatever fuelis in the locomotive’s tank at the timeof testing.The Agency recognizes that thepotential exists for future locomotives toinclude additional power notches, oreven continuously variable throttles,and is proposing alternate testingrequirements for such locomotives.Using the proposed FTP for suchlocomotives would result in anemissions measurement that does notaccurately reflect their in-use emissionsperformance because it would not be areasonable representation of their in-useoperation. Thus, locomotives havingadditional notches would be tested ateach notch, and the mass emission ratesfor the additional notches would beaveraged with the nearest ‘‘standard’’notch. Locomotives havingcontinuously variable throttles would betested at idle, dynamic brake, and 15power levels assigned by theAdministrator (including full power),with average emission rates for twopower levels (excluding full power)assigned to the nearest ‘‘standard’’notch. The 15 power levels proposedrepresent one level for full power andtwo, to be averaged, for each of theseven intermediate power levels usedon current locomotives. TheAdministrator would retain theauthority to prescribe other proceduresfor alternate throttle/powerconfigurations.D.2. FTP for EnginesThe proposed test procedures areintended primarily for the testing oflocomotives, rather than locomotiveengines. However, EPA does recognizethat engine testing will be reasonable insome cases, such as data collection froma development engine. For these cases,the engine would be mounted on astand, with its crankshaft attached to anelectric dynamometer. Because theAgency believes that it is critical thatengine testing be as representative ofactual locomotive operation as canpractically be achieved, it is proposingthat important operating conditionssuch as engine speed, engine load, andthe temperature of the charge air