Field Test Results of Soybean-Based Rail Flange Greases Using High Rail and Way Side Application Methods

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1 Field Test Results of Soybean-Based Rail Flange Greases Using High Rail and Way Side Application Methods AREMA Annual Conference 2000 Dallas, Texas Dr. Lou A.T. Honary Associate Professor and Director University of Northern Iowa (UNI) Ag-Based Industrial Lubricants (ABIL) Research Program June 2000

2 Field Test Results of Soybean-Based Rail Flange Greases Using High Rail and Way Side Application Methods ABSTRACT In addition to reducing noise and track wear, there are indications that a considerable amount of fuel savings can also be realized by using flange lubricant around track curves, with additional potential by applying it on straight-aways. Given the volume of fuel used, these savings are substantial relative to the cost of application. One concern however relates to long-term build up and/or seepage of the grease and the liability potential associated with existing or prospective regulatory actions. Using soybean oil, which is considered "readily" biodegradable according to EPA standards, improves the long-term cost potential of using flange lubricant. More importantly, soybean base oils have been proven to provide inherently higher lubricity, better adherence to metal, better tackification, higher thin-film strength, higher flash and fire points, and higher viscosity index than conventional base oils. UNI-ABIL has developed and tested soybean-based high-rail flange lubricants that, in field studies demonstrated superior application features, thin-film durability that lasted longer than conventional greases, and high-temperature performance that resulted in stable performance in high summer temperatures. The aluminum complex formulation appears to be cost competitive when evaluated on the basis of operating life, and also has very acceptable environmental and toxicity features. With guidance from a leading Class I railroad company, a key equipment supplier, and major lubricant manufacturer, UNI-ABIL has since re-formulated the high-rail blend for wayside application as well. Field studies of this version are expected to demonstrate similar performance, and large-scale commercialization is expected in 2000.

3 As USA is the largest producer of soybean in the world, and because of the lower cost of soybean oil compared to other vegetable oils, these greases are providing superior performance with little or no price penalty. This report will present performance data observed in the laboratory and those gathered from the field through observation and operator interviews. Other aspects such as cost and environmental benefits will also be included.

4 Field Test Results of Soybean-Based Rail Flange Greases Using High Rail and Way Side Application Methods INTRODUCTION For years crop growers in the United States and Europe have searched for new uses for their crops in order to improve market stability through diversification and reduced surpluses. The use of vegetable oils for fuel and lubricants is not new. In the 20 th century both World Wars and petroleum shortages renewed interest in the use of crop oils for fuel and lubricants. The University of Northern Iowa s Agriculture-Based Industrial Lubricants (UNI-ABIL) Research Program was established in 1991, through a grant from the Iowa Soybean Promotion Board. It s mission is to expand the market for American-grown crops through use in industrial lubricants. The program s research has resulted in patents for the first soybean-based tractor hydraulic fluid, a soybean-based transformer coolant, and in commercialization of other industrial greases and lubricants. Over the past nine years, performance data on the major seed oils such as rapeseed, canola, sunflower, cotton, palm, and soybean have been compiled. Furthermore, when available, genetically modified varieties of these seed oils have been analyzed in order to determine their suitability for use in industrial lubricants. The purpose of this report was to focus on the field test results of greases made with two different soybean base-oils with different thickeners. Soybean oil with biodegradable and natural thickeners was used; in creating a Biobased finished product.

5 Pursuant to extensive laboratory testing, the field tests were mainly based on operators assessment of the grease performance. When possible, company data on the grease usage were analyzed to determine the impact of the grease on the particular operation. The rail grease was tested at an Iowa-based railroad with 300 miles of track running east to west across the entire state of Iowa. Additional testing of the grease is underway at class I railroads around the country. While the testing is expected to continue, some of these products have been commercialized and are on the market. SOYBEAN OIL The U.S. is a leader in the production of soybeans, producing approximately half the entire world production. In 1998, 2.7 billion bushels of soybeans were produced in the U.S. Each bushel of soybeans, yields about 11 lbs. of oil. This is about 1.3 gallons of oil per bushel, making the U.S. soy oil production a large volume of over 3.6 billion gallons (at 2.7 billion bushels produced annually by some 442,000 farmers). INDUSTRIAL LUBRICANTS A report by the National Petrochemical Refiners Association (NPRA) indicates that U.S. oil companies sold over 909 million gallons of industrial lubricants in 1992 (NPRA, 1993, 1992 Report on U.S. Lubricating Oil-Sales). Also, an additional 1.3 billion gallons of automotive oils were sold during that year, for a total of over 2.2 billion gallons of annual sales. Industrial lubricants, according to NPRA, present an array of products that include: general industrial oils, hydraulic fluids, metal working oils, and process oils. Each of these areas contains a variety of other oil applications with their own unique requirements.

6 OXIDATIVE STABILITY Vegetable oils have two major shortcomings when considered for use in greases, a) lack of oxidative stability; and b) high pour point. The pour point (a temperature point where a cooled liquid stops having movement) can be addressed by use of pour point depressants and or by blending with liquids with low pour point properties. However, the oxidative stability is a more complex problem, which needs to be addressed differently based on the intended application. Greases that require high processing temperatures, over 150 C, are particularly troublesome for most vegetable oils. When exposed to high blending temperatures the oil may initiate polymerization without being noticed. Chemical modifications including hydrogenation and use of chemical antioxidants have been used to stabilize vegetable oils. Using partially hydrogenated soybean oil, which was winterized to improve its pour point, greases were developed using selected thickeners. Provided that shelf life is not an issue, greases that do not require high processing temperatures can use soybean and other vegetable oils. If shelf life is important then the oil will have to be stabilized. Using stabilized soybean oils selected thickeners were used in preparation rail curve greases. Thickeners used were selected based on their environmental friendliness or biodegradability. They included clay and aluminum complex. Table 1 shows performance characteristics of a clay-based grease.

7 Description Value Standard Test Method NLGI Grade 1 Thickener Type Clay Filler Type Graphite Appearance Black Visual Cone Penetration, worked 60 strokes 325 ASTM D-0217 Dropping Point, o C ( o F) 260 o C (500 o F) ASTM D Ball Wear Test 0.60 ASTM D Ball EP, Load Wear Index 43 ASTM D-2596 Scar Diameters (mm) at last non-seizure ASTM D-2596 load (80 Kg) 0.44 Weld Load, Kg 250 ASTM D-2596 Base Oil 40 o C, cst 36 ASTM 90 o C, cst 9.5 ASTM D-0445 Viscosity Index 248 ASTM D-2270 Pour Point o C ( o F) -8 o C (-17.6 o F) ASTM D-0097 Flash Point o C ( o F) 326 o C (618.8 o F) ASTM D-0092 Fire Point o C ( o F) 358 o C (676.4 o F) ASTM D-0092 Humidity Cabinet Test (100 hours) Pass ASTM D-1748 Base Oil Biodegradability * Pass Pass CEC L-33-A93 Mod. Sturm OECD 301B Base Oil Aquatic Toxicity (Daphnia) Non-toxic LC50 >1000 PPM Table 1: Performance Characteristics of a Clay-based Grease The clay-based grease requires minimum amount of performance enhancing additives making the finished product almost entirely biobased. The aluminum complex grease too provides high degree of biodegradability being soybean-based and using biodegradable aluminum complex thickener. The majority of the field tests were based on the aluminum complex grease; although lithium-based greases using soybean oil have been developed and tested as well. Table 2 shows performance characteristics of aluminum complex grease.

8 NLGI Grade ASTM Method Product Number or Name Winter Summer Appearance Black Black Visual Cone Penetration, Unworked (0 strokes) D-217 Worked 60 Strokes D-217 Worked 10,000 Strokes D-217 Dropping Point, C 100 b 266 D-2265 Dropping Point, F 212 b 510 D-2265 Base Oil Viscosity 40 C, cst C, cst Ball EP, Load Wear Index (LWI), kgf D-2596 Lost Non-Seizure Load, Kg 63 Scar Dia. At above Load, mm Ball EP Weld Point (Weld Load), kgf D Ball Wear Scar, mm 0.51 D-2266 Modified 4-Ball Wear-Scar b, mm (D-2266) c Soap Type Base oil properties are shown in Table 1 Aluminum Complex Aluminum Complex Table 2: Performance Characteristics of an Aluminum-based Grease Rail/flange greases are usually applied in one of three ways. A high rail uses a road truck fitted Figure 1: The Nozzle of a High Rail Grease Applicator Next to the Track

9 with a set of flanged wheels and two applicators, which apply the grease to the sides of the tracks. Typically a 30 psi-air pressure source is used to force the grease through the nozzles of the applicator. Figure 1 shows the nozzle of grease applicator next to the track. The second method is a way-side application method where a bar attached to the rail disburses the grease to the side of the track section while the train is passing that section. This too requires some pumping action triggered by the approaching train. See Figure 2. Figure 2: Wayside Grease Applicator in a Laboratory Set-up The third method utilizes a locomotive-based greaser which pumps the grease from an on-board grease reservoir through hoses and tubes to the wheel flanges. This method requires a thinner grease to flow through the lines and to the wheel flange and the track. The soybean-based grease in the Iowa-based railroad test used a high rail grease application method. The same grease with a higher viscosity (grade 2 vs. grade 000) is being tested in several wayside applicators. The results of the later are not available at the time of this reporting.

10 The measurement of the rail profile, which took place at the beginning of the field test, will need to be repeated to determine wear on test sections. Because the company greases the entire length of the track (vs. only curves as some companies do), attempts were made to determine fuel savings and wear protection gains. Intensive analysis of the Gross Ton Miles and fuel use indicated significant gains in fuel saving when tracks were greased. However, the data included many variables beyond the researchers control and thus scientifically unreliable. The company, however, considers the savings significant enough to warrant continuing to grease the entire track throughout the year. The assumption is that on the straight-aways the train oscillates side to side and a greased track reduces the drag of the flange against the track-side thus improving fuel efficiency. The wear studies, too, showed much variability on the train wheels as they are replaced but not recorded. However, the track wear will be reportable when the post-test measurements are taken on the third anniversary of the test commencement. Qualitative results as reported by the operator were compiled. The operator drives the truck home and every morning, when on greasing assignment, the operator enters the track and begins greasing as many miles as possible within the working day. A 30-gallon reservoir placed on the truck bed is fitted with a supply of air at 30 psi. The operator is very experienced with this operation and can tell the degree of dryness on the track from the sound of the truck s flanged wheel on the tracks. According to driver observation, soybean grease presents two distinct advantages. First, the grease persists on the track for longer periods of time than previously used conventional greases do. The operator had observed that with conventional grease certain sections of the track with the same gross ton-miles would be completely dry within approximately two weeks, when re-

11 greasing was scheduled. With the soy-based grease, after the scheduled two weeks, the track showed significant amounts of lubricant present, thus the track would not feel as dry as the as it did in the past. Two reasons for the persistence of the soy-based grease on the track are hypothesized. One, due to a vegetable-based base-oil, the grease adheres better to the metal surface of the track thus lasting longer. Two, perhaps at high pressure, and high pressure induced temperatures, along with repeated use, a micro layer of polymer coating covers the track thus providing the continued greased feel of the track. The first hypothesis is confirmed through previous work. The second one, however, is being investigated. The second advantage of the grease as observed by the operator dealt with application during high summer temperatures. Applicator nozzles are normally held very close, ¼ - ½ to the track. According to operator observations, on hot days when ambient temperature is around 90 F (32.22 C), for example, the track temperature approaches 130 F (54.44 C). At such temperatures the conventional greases would thin down where as the soy-based grease maintained more of the same thickness. This feature became particularly important on hot windy days because the wind would blow thinned-down grease to the top of the rail, which creates slippage for the locomotive wheels, and loss of fuel efficiency and other problems. In extreme cases, sand has to be used on top of the rail to create friction. Stability of the soy-based grease at high temperatures is attributed to the high Viscosity Index of the base soybean-oil at 223 as compared to petroleum base oils at around 120. Viscosity Index is a measure of oil s resistance to change viscosity as temperature changes. Oil with a high viscosity index will not thin down when exposed to high temperatures as does oil with a lower VI. Affirmation of this scientific fact by field operator should lead to other uses where a more stable product at higher temperatures is required.

12 Some rail operators have expressed concerns about accumulation of large quantities of grease under the locomotive and the rail cars. Sparks during breaking, heat generated due to friction at curves and other sources of ignition could create fire hazards. But, the real problem has been when open flames used for welding near grease tanks at track-side has ignited greases with a high flash point. The base soybean oil has a flash point of F (or 326 C). While not completely fireproof, the high flash point will provide an additional benefit to vegetable-based greases that are considered renewable and earth-friendly. CONCLUSIONS Greases made of soybean oil appear to present certain performance benefits. The field tests used to evaluate two greases made of soybean oils were mainly subjective and relied on operator assessment. While the operator observations verified performance observed in the laboratory, there is a need for quantitative studies of wear protection, fuel savings, and persistency in use. Several tests exist for wear protection properties of the grease on flanged wheels and tracks. Industry based controlled field test facilities can perform more accurate evaluations of these greases as well. This study, however, indicates that greases made of soybean oil present potential as a viable lubricant. Further use and field data should help identify improvements, if any are needed. Finally, due to the abundance of soybean oil and its relatively low prices, the cost of finished greases is low to the point of being almost competitive with conventional greases. Furthermore, increasing petroleum prices in the U.S. combined with production of naturally more stable soybean oil through genetic variations are expected to result in high quality greases at competitive prices.

13 REFERENCES Honary, Lou. (1996). An Investigation of the Use of Soybean Oil in Hydraulic Systems, Bioresource Technology. Great Britain: Elsevier Science Limited. Naegley, P.C. (1992). Environmentally Friendly Acceptable Lubricants. Lubrizol Corporation, Wickliffe, Ohio. NPRA (1993) Report on U.S. Lubricating Oil-Sales. National Petrochemical Refiners Association, Washington, D.C.