High Axle Load Research Articles

Effect of high-axle load traffic on subsoil physical properties and crop yields in the Pacific Northwest USA

Cultural practices for winter wheat production in the Pacific Northwest USA include rotations with spring crops. These cultural practices result in heavy wheel traffic (≥ 9 Mg per axle) during wet soil conditions, which could result in serious soil compaction. A field experiment was initiated in the spring of 1986 near Moscow, Idaho, USA, on a silt loam soil to determine the effect of heavy axle loads on subsoil physical properties and crop yields. Compaction treatments consisted of axle loads of < 5 (check), 10, and 20 Mg applied track-to-track four times at experiment initiation. Bulk density and impedance within the subsoil were increased by the 10 and 20 Mg loads to a depth of 0.75 m. The effects of the one-time high axle load traffic persisted after 3 years. Crop yields were not significantly reduced by the soil physical conditions resulting from the 10 Mg load. Compaction resulting from the 20 Mg load limited root growth and reduced subsoil water extraction.

Influence of high axle loads and tillage systems on soil properties and grain corn yield

The effects of various tillage systems in combination with different levels of high axle load traffic on soil bulk density, penetration resistance and corn ( Zea mays L.) grain yields were studied for a 3 year period on a silt loam soil. The tillage systems were zero tillage, fall chisel plowing and fall moldboard plowing. Traffic treatments involved the annual post-harvest imposition of a 12 Mg axle weight on 100%, 25%, and 0% of the plot surface area. The 0% treatment involved controlling all field traffic with the use of a wide span tractor. Only in the third year were differences in soil bulk density resulting from loading significant within all three tillage systems at the 5–10 cm depth interval. At a depth of 20–25 cm (below the maximum depth of tillage) differences in soil bulk density resulting from loading were never significant regardless of the tillage system or year. Differences in penetrometer resistance in the 0–10 cm depth interval resulting from loading were generally only significant in zero tillage, but they were often significant within all tillage systems in the 12–22 cm depth interval. The maximum depth to which loading caused significant increases in penetrometer resistance was 35 cm. Corn grain yields were significantly higher for the traffic-free treatments within only one tillage system (moldboard) in only 1 year (1988) of the experiment. In general, axle loads of 12 Mg did not result in reduced grain corn yields regardless of whether they were imposed on 25% or 100% of the plot surface area.

Long-term effects of a single incidence of high axle load compaction on a clay soil in Quebec

The long-term effects of a single incidence of compactive loads of 12 and 20 Mg per axle on a clay soil are evaluated. Changes in soil bulk density and crop performance under monocultural row production were monitored over the 7 year period following loading. Soil bulk densities were significantly increased by the initial high axle load compaction. Bulk densities in both compacted and uncompacted plots continued to increase in a monocultural corn production system. The effect of residual compaction on total plant dry matter yields lasted for 4 years. Grain yield reductions persisted for up to 6 years after compaction. In both cases, however, yields showed an improving trend throughout the study period.

A model for estimating crop yield losses caused by soil compaction

A computerized empirical model for estimating the crop yield losses caused by machinery-induced soil compaction and the value of various countermeasures is presented, along with some examples of estimations made with it. The model is based mainly on results of Swedish field trials, and predicts the effects of compaction in a tillage system that includes mouldboard ploughing. It is designed for use at farm level and predicts four categories of effects: (1) Effects of recompaction after ploughing. The calculations are based on the wheel track distribution in the field and the relationship between “degree of compactness” of the plough layer and crop yield. (2) Effects of plough layer compaction persisting after ploughing. Crop yield losses are estimated from traffic intensity in Mgkm ha −1 (Mgkm = the product of the weight of a machine and the distance driven), soil moisture content, tyre inflation pressure and clay content. (3) Effects of subsoil compaction. The calculations are similar to those presented under point (2), but only vehicles with high axle load are considered. These effects are the most persistent. (4) Effects of traffic in ley crops. The estimations are based on wheel track distribution, soil moisture content and several other factors.

Rolling contact fatigue in railway wheels under high axle loads

Rolling contact fatigue defects are encountered in railway wheels used under high axle load conditions, in which substantial reductions in rail and wheel wear rates have been obtained through the previous introduction of higher strength materials and modified wheel and rail profiles. The metallurgical characteristics associated with defect initiation and growth are described. A fatigue initiation criterion based on exceedence of shakedown limits for the two wheel materials concerned has been assumed. An analysis of wheel-rail contact conditions in curved and tangent track was undertaken to identify which combinations of wheel load, wheel and rail profiles and vehicle dynamics result in stress levels which exceed shakedown limits. This analysis is supported by full-scale tests involving continuous monitoring of wheel-rail contact. Extreme dynamic loads, leading to the initiation of isolated defects, are more likely to occur on tangent track, while curved track conditions will favour fatigue crack growth, when contact geometry and vehicle tracking combine to concentrate higher stress cycles in the initiation zone. Additional field tests, using an instrumented vehicle, will be carried out to confirm these findings and allow appropriate remedial action to be identified.

Compaction characteristics for the towed and driven conditions of a wheel operating in an agricultural soil

High axle loads, duration of strain as well as strain rate due to applied stresses, and field moisture condition have been found to contribute to compaction in the field. Numerous previous investigations on agricultural soil compaction were carried out with relatively dry soil. The aim of this study was to investigate the interrelationships between compaction, applied load, vehicle speed and a certain practical range of soil moisture content through a soil bin investigation of the compaction which results from the passage of a towed and a driven wheel. Soil pressure and the corresponding bulk density were analysed using a model proposed by Bailey et al. ( J. agric Engng Res. 33, 257–262 (1986)) and ANOVA techniques. The results showed that compaction was higher at the higher moisture content level for both towed and driven conditions of the wheel, and that it was applied load that had the greatest contributory effect. Also, compaction was higher in the case of the driven wheel as compared to the towed wheel due to the phenomenon of slip sinkage. Bailey's model, it appears, can be utilized in the field for a practical estimation of compaction resulting from the passage of a towed wheel.

Corn Growth and Yield as Affected by Surface and Subsoil Compaction

AbstractWheel traffic of harvesting operations on agricultural fields often carries compactive loads in excess of 8 Mg. Consequently, soil physical properties may be affected to depths of 60 cm, and these effects of compaction may persist for a number of years. In addition, smaller compactive forces that affect only the surface layer of soil are applied annually during spring tillage and planting operations. A replicated field study was conducted on a Webster clay loam (fine‐loamy, mixed, mesic Typic Haplaquolls) in southern Minnesota, and two Ves clay loams (fine‐loamy, mixed, mesic Udic Haplustolls) in southwestern Minnesota to assess the effects of surface and subsoil compaction on the growth and yield of corn (Zea mays L.). A total of six compaction treatments was imposed; subsoil compaction of control (no subsoil compaction), 9 Mg per axle, and 18 Mg per axle loads, each with and without annually applied interrow surface compaction of &lt;4.5 Mg per axle. During the first year after high axle loading, 9 and 18 Mg per axle loads significantly decreased final grain yield by 9 and 30%, respectively, on the Webster soil. For the second year, the 18 Mg per axle treatment significantly reduced yield by 12% as compared with the control treatment. Soil water loss data indicated a more shallow rooting depth and/or reduced root activity in the 18 Mg per axle treatment. High axle loads on a dry Ves soil caused little subsoil compaction; grain yield was reduced by only 6% the first year after high axle loading. High axle loads on a relatively wet Ves soil compacted the soil to a depth of 60 cm. However, relatively dry climatic conditions the following year negated any potential adverse effects of subsoil compaction and yields were not affected. Surface layer compaction from annual interrow wheel traffic did not cause a significant yield response consistently at any site.

Effect of high axle-load traffic on subsoil compaction and crop yield in humid regions with annual freezing

The weight of agricultural machines is steadily increasing, and this leads to higher axle load and deeper subsoil compaction. As an international joint effort, the effects of high axle load traffic on subsoil compaction and crop yield are being studied in 26 field experiments in Europe and North America. Results at present available, applicable to humid areas with annual freezing, show that crop yield losses normally become larger and more persistent with increasing soil clay content. The results indicate that restrictions upon axle loads are required.

Cumulative High Axle Load Compaction in a Loam Soil

A 3-year study on the effect of annual compaction by heavy axle loads was conducted in a loam soil. Each year, loads of 10 and 20 t/axle were applied at two soil moisture contents. The resulting changes in soil bulk density to a depth of 0.6 m and crop response were monitored during each growing season. The loam soil was able to sustain cumulative annual compaction with little structural change due to an existing coarse, naturally dense subsoil with high bearing capacity. Most compactive changes were limited to the topsoil where alleviation by tillage could easily be effected. Compaction effects on crop growth were limited to the early stages. There were no reductions in crop yield due to the 10 t/axle loading. The 20 t/axle treatment however significantly reduced total plant dry matter yields.

Natural Alleviation of High Axle Load Induced Compaction in a Loam Soil

STUDIES were carried out to determine the natural alleviation of compaction induced by heavy axle loads in a loam soil. 10 and 20 t/axle were applied at two soil moisture contents in May, 1982, following which soil density changes and crop growth and yields were monitored for three growing seasons. Initial soil density changes were minimal due to an existing coarse, naturally dense subsoil and third year investigations showed that soil density and crop yields in compacted plots were not significantly different from those in control plots.

Crop response to high axle loads in Minnesota

Crop response to high axle loads in Minnesota

Extent and Persistence of Subsoil Compaction Caused by Heavy Axle Loads

AbstractWheel traffic of heavy farm machinery is causing increased concerns about soil compaction. To offset the increasing weight of large equipment, tires have increased in both size and numbers in an effort to keep constant the contact pressure on the soil surface. Recent research has indicated, however, that increasing axle load can cause increasing and deeper compaction irrespective of surface contact pressure. Axle loads of 9 and 18 Mg were applied in replicated field experiments initiated in 1981 and 1982 in Minnesota as part of an international cooperative study on the effects of high axle loads on deep soil compaction and plant response. Such axle loads are typical of modern harvest and transport equipment. These heavy axle loads were applied only at the beginning of the experiment, and are compared with check treatments where axle loads are limited to ≤4.5 Mg. Various soil parameters were measured to assess the extent and persistence of subsoil compaction. When the subsoil was relatively dry, axle loads of 9 and 18 Mg did not cause significant changes in bulk density, penetrometer resistance, or hydraulic conductivity deeper than about 20 to 30 cm, the normal depth of tillage. However, when the subsoil was relatively wet, bulk density increased about 0.08 Mg m−3 from about the 30‐ to 50‐cm depth. Saturated hydraulic conductivity decreased from 2 to 0.2 cm h−1 due to 18‐Mg axle load on a Webster clay loam (Typic Haplaquolls). A similar relative decrease was measured on a Nicollet clay loam (Aquic Hapludolls). Evidence of subsoil compaction persistence was measured 4 yr after initial heavy axle loading in spite of annual winter soil freezing to depths up to 90 cm.

Swedish experiments on subsoil compaction by vehicles with high axle load

Abstract. Soil and crop responses to traffic with vehicles having an axle load of 10 tonnes were studied in 9 field experiments. The clay content of the soils ranged from 6 to 85%. The traffic resulted in increased soil bulk density and strength to a depth of 50 cm. Compaction effects persisted below plough depth 7–8 years after traffic. Crop response was negative and increased with clay content of the soil and with traffic intensity and decreased with time. The results indicate that maximum axle loads on arable fields should be less than 10 tonnes, especially on clay soils.

High Axle Load Compaction and Corn Yield

ABSTRACT AN experiment was set up to study the effect of high axle loads on subsoil compaction and corn production in two soil textures. Treatments of 10 and 20 t/axle were applied at two soil moisture contents. Resulting changes in soil physical characteristics as compared to a control were measured to a depth of 0.60 m. Topsoil and subsoil dry density levels were significantly increased by high axle loads. Moldboard plowing of compacted plots to a depth of 0.20 m did not fully relieve topsoil compaction. Because of the small difference between them, the two soil moisture contents at the time of compaction had little effect on topsoil or subsoil bulk density in either field. The incurred soil structural changes had minimal effect on the growth and maturity of grain corn in the loam field. However, yields were significantly decreased by compactive loading. Both moisture and compaction treatments significantly modified the rate of plant growth, maturity and yields in the clay field...

Road damage and the vehicle

In recent years there has been an increasing awareness of a relationship between road damage and high axle-loads. The heavy-vehicle operator constantly seeks new legislation permitting the use of larger vehicles to achieve economies of scale while the controller of the highway network resists such pressure to contain maintenance and protect the environment. This article examines the factors that influence the amount of road damage inflicted by a vehicle and identifies the options that exist to minimize it.

Modern Development in Rail Steel Metallurgy and Production

Modern railway transportation, progressing towards ever higher speeds, higher axle loads and greater traffic volumes, places high demands on rail steel. The rails should have a high resistance to wear and fatigue, be weldable, and display safety against fracture.Steel producers have met these requirements with the help of metallurgical research: rails as described above should have a fine grained pearlitic microstructure and small interlamellar spacing with a tensile strength of up to 1300 N mm—2. This microstructure can either be achieved by heat treatment of the rail, or by the addition of alloying elements to the rail steel. Both types of rail show satisfactory service performance. In addition to these, novel types of rail steels are also being track-tested at present.Rail steel is mainly produced by the BOF process, followed by casting into hot-top ingot moulds or by continuous casting. Under suitable deoxidizing and casting conditions a low content of non-metallic inclusions is ensured. Controlled cooling of the rails can be obviated by employing low-hydrogen melting or by vacuum degassing. Prior to shipment the rails are inspected ultrasonically, only internally sound rails without shatter cracks and with a high degree of cleanliness being supplied. Résumé Le transport moderne ferroviaire, qui s'avance toujours vers des vitesses accrues, des charges d'essieux plus lourdes et des volumes de trafic plus importants imposent des exigences sévères sur l'acier à rail. Les rails doivent posséder une grande résistance à l'usure et à la fatigue, doivent etre possibles à souder, et doivent se montrer resistant à la rupture.Les producteurs d'aciers ont rencontré ces exigences avec l'aide des recherches en metallurgie. Les rails tels que décrits ci-haut doivent posséder une microstructure a grains fins et perlitique à distance interlamellaire réduit, avec une résistance en traction de jusqu'a 1300 N mm−2. Cette microstructure peut être réussie soit par traitement thermique du rail, soit par Ie moyen d'alliage. Les deux sortes de rail montrent un comportement satisfaisant en service. En plus de ceux-ci, des aciers à rails nouveaux sont actuellement à l'epreuve dans des voies.L'acier a rail est produit surtout par le procédé BOF, suivi de coulée dans des lingots a tête chaude on par la coulée continue. Sous des conditions convenables de désoxidation et de coulie, un contenu réduit d'inc1usions non-métalliques est assure. Le besoin de refroidissment contrôlle peut être êvitê par la coulée à contamination réduite d'hydrogène ou par dégazage sous vide. Avant la livraison, les rails sont inspectés a l'ultrason et seulement des rails solides, sans “shatter cracks” (fissures) et très propres sont expédiés.

West Coast Main Line Operational Performance following Electrification from Weaver Junction to Glasgow

Some of the problems experienced since the electrification of the line from Weaver Junction to Glasgow are described and the solutions adopted explained. These include the failure of the overhead line at neutral sections, rail damage caused by high axle loads, tyre damage due to braking problems, loss of adhesion on gradients and improvements to the sanding gear. The paper concludes with a section on the problems of the thyristor locomotive.

Long-distance Diesel 'Buses on the European Continent

In this paper the author deals with the special requirements for Diesel 'buses used for long-distance travel on the European continent. These 'buses travel over flat and mountainous countries, covering distances of between 300–400 miles per day at a regular speed of 50–60 m.p.h., while between 70 and 75 m.p.h. must be maintained on German Reichs-Autobahnen. As they are regularly operated in the Alps they must have a high continuous output when working on long and steep gradients. The 'bus must be capable of climbing a gradient of approximately 20 per cent (1 in 5), and this necessitates a heavier transmission than is required in normal use. It is also essential that gear changing can be easily carried out. With steep gradients the normal braking system is not capable of doing all the work and it is therefore necessary to fit a special exhaust brake to the engine; details of this brake and the results obtained by fitting it are given. The influence of a throttle valve in the air intake is discussed. Light steering and a small turning circle are important when descending steep gradients, and the high front axle load of approximately 5,000 kg. when descending necessitates special springs and tyres.