Vegetationsbekämpning på banvallar
Hansson, David; Mattsson, Berit; Schroeder, Håkan
Sweden’s National Rail Administration (Banverket) is in charge of approximately l0 000 km of railroad track, of which 750 km are restricted sections where chemical weed control may not be used. Each individual restricted part is relatively short (under 100 metres). Today, there is no weed control carried out in the restricted areas. In general, weed control is necessary because otherwise the safety of the track would deteriorate, with a growing risk for subsidence, engine skidding, and fire etc. Knowledge about the extent of the problems and the mechanisms behind how weeds affect embankments is very limited, however. When changing to non-chemical weed control, well established root-propagated weeds supplied by an extensive system of roots or stems in the embankment and adjoining areas, are difficult to combat. In gravel, however, a large part of the weeds come from weed seeds that have germinated in the surface of the gravel ballast. These weeds are easy to control if treatment is started when they are small. Preventive measures are used partly to prevent roots and underground stems from growing into the embankment and partly to prevent seeds from establishing themselves and germinating in the ballast surface. Examples of preventive measures are; changing/cleaning the ballast, using weed barriers and planting vegetation that competes with weeds on adjoining surfaces. Cleaning the ballast is too expensive a step to be motivated by weeds only. Using weed barriers should be a successful method if applied when building new constructions and in combination with ballast cleaning. In order to improve the effectiveness of the method, it is necessary to develop materials and construction methods further. In this report different non-chemical weed control methods are being compared from a technical, economical, environmental and working environmental point of view. The feasibility of brush weeding, flaming, hot air, hot water, steam, electrothermal weed control and UV-radiation for weed control on railway embankments is being discussed. Methods of controlling growing weeds can be divided into mechanical control and thermal control. Thermal control does not involve physical contact, that is, it can be carried out without any contact between machine and plant/embankment. Mechanical control, for example brushing, means that also the ballast material is being treated. Signals, poles, cables, switches etc. in the railway environment are obstacles and limitations to which new control methods must be adapted. When going over to new methods, it is important to know how these affect both the surrounding environment as well as the working environment for the employees who implement them. The working environment is to a large extent determined by the properties of the machines used and to a smaller extent by the control method. Since diesel is a common fuel, the emissions from the combustion engine represent a major influence on the environment. Improved purifying methods and, in the long run, the disuse of fossil fuels is a necessary development to reduce the burden on the environment. This study shows that for certain methods there is not enough material to evaluate their practical usefulness (for example UV-light). In other cases, the fundamental theoretical knowledge of the methods is fairly good, whereas the practical experience is inadequate as a basis for deciding to try them out on a large scale. The report gives suggestions for continued R&D-activities on both a long-term and a short-term basis in order to attain a more efficient exploitation of resources in a development phase. When introducing new methods, information material must be supplied aimed at target groups both among buyers and those who implement them. While this study was being carried out, several international contacts have been made and it is natural for this international exchange to be developed further in the continuing work with vegetation control on embankments.
Rapport - Sveriges lantbruksuniversitet, Institutionen för lantbruksteknik
Publisher: Institutionen för lantbruksteknik, Sveriges lantbruksuniversitet
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