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Spraying system eliminates weeds that hinder the locomotion of trains


They seem inoffensive, but the weeds that grow alongside or between the rails of the train can cause many problems. These invasive plants, when they are quite dry, are transformed into inflammable material, causing fires very easily. And in the periods with greater intensity of rain on the tracks, they cause the wheels to skid, preventing the train from leaving the place, besides making drainage of the permanent way more difficult. This accumulation of water also leads to the premature rotting of the sleepers – those pieces of wood that lie under the tracks. The weeds hide the sleepers, making it impossible to see whether they are rotten and hence whether it is time to replace them. Shortcomings in maintenance may cause more serious accidents, like the derailing of trains. This problem always disquieted the engineer during the 25 years in which he worked for Ferrovia Paulista S/A, the former Fepasa. Now he has a solution.

“Since 1988, we have been perfecting a herbicide spraying system, to eliminate only the plants that really hinder the locomotion of the trains, without leaving the slopes devoid of plant protection (with the soil instable and silted up) in the rainy seasons”, Nogueira says. The solution to the problem arose in Infrajato, a company from the city of Botucatu, São Paulo, in which he is a partner. The new system is a result of a partnership with the Faculty of Agronomic Sciences of the São Paulo State University (Unesp), in the same city, in a project that received financing from FAPESP’s Small Business Innovation Research Program (PIPE).  The project was coordinated by Professor Ulisses Rocha Antuniassi and uses principles of the so-called “precision farming”, in which various technological resources are used to solve problems in the field.

The basic structure for the system to function is made up of a locomotive and four wagons. The first of them serves as a dormitory for the technical operators of the machine. The two following wagons have, respectively, herbicide, and workshop and water. In the last wagon, there is the railroad sprayer, with a climatized cabin where the four onboard computers are that control the spraying, together with the GPS (Global Positioning System) that indicates the exact places for applying the herbicide.

Before the first application, the locomotive does the journey over the route to map the whole itinerary. In the onboard computers, which coordinate the system, the application is programmed in accordance with the environmental legislation corresponding to each state through which the train is going to pass. For example, if in the state of Mato Grosso the application of herbicide is not allowed in regions with a distance of up to 100 meters from some river, the system obeys this legislation and takes a break in the prohibited regions.

As the undergrowth that grows in the stone ballast trails more in comparison with the undergrowth that invades the region besides the rails, the researchers have developed a system with three spray bars. Each one of them applies the quantity of herbicide strictly necessary in the three regions of the rails. One bar distributes herbicide between the rails, and the other two do so to the left and the right of the train. With the same intention of achieving a controlled spraying, the team developed a system that only mixes the herbicide the moment it is applied.

The use of techniques to control the growth of weeds where the rails of the train are is work just as old as the dissemination and use of this means of transport that goes back to the 19th century. Throughout time, the weeding was done manually and called for a lot of labor, at a very high cost. The chemical control of the growth of these plants, which came into existence in the 1950’s, was a resource adopted to make this job cheaper. Nogueira remembers that in the 1970’s there was an evolution in herbicides. These products ceased to have a very great residual effect, capable of contaminating the environment around the railroad line due to the high doses used.

At the end of the 1980’s, by means of a technological development agreement between Fepasa, Unesp and Monsanto, a handcar (a small wagon) was developed to apply herbicide. The measure brought enormous savings to the railroad. The funds necessary for performing the same work came to represent only 2% of what used to be spent with the manual weeding of the undergrowth. Together with the mobilizations in favor of the environment, which happened more intensively in the 1990’s, there came to be a greater demand for control over the use of herbicides. It was around 1998 that the team coordinated by Professor Antuniassi began to look for alternatives for controlled spraying.

INFRAJATOThe last wagon distributes herbicide and eliminates the undergrowth common in Brazilian railroadsINFRAJATO

“The advantage of the sprayer for the environment is that it makes a safer application”, the engineer explains. The new system is capable of carrying out in one day the work that its previous prototype would take up to a month to do. “In the old distribution system, the wagon would stop to fill up. That would hinder the railroad traffic and make the job longer to do. Now the formation runs over 300 kilometers without a pause”, he says. As the application is only carried out in places that are really necessary, the system saves herbicide, and in some regions there is a reduction of up to 30% of the product.

The sprayer developed between 2001 and 2004 was delivered to Brasil Ferrovias by means of a two year contract and has been used in 14% of the Brazilian railroad network. With the recent purchase of this company by ALL Logística, the engineer does not yet know whether there will be a renewal of the contract that will guarantee the continuity of the service. In the meantime, Infrajato is preparing a second sprayer that it intends to offer to other railroads. For Professor Antuniassi, the new system has great potential applicability in Brazil. “There are over 30 thousand kilometers of railroad in use, mainly for freight transport.”

The Project
Development of systems for localized application and rationalization of the technology for applying herbicides in railroads (nº 00/12124-6); Modality Small Business Innovation Research Program (PIPE); Coordinator Ulisses Rocha Antuniassi – Infrajato/Unesp; Investment R$ 88,919.00 and US$ 39,553.50 (FAPESP)