M.Y. Smirnov, Y.S. Andrianov ( Russia, Yoshkar-Ola, Mari State University of Technik)


Рассматриваются основные проблемы вывозки  сортиментов  самозагружающимися автопоездами. Рассматриваются основные задачи для решения эффективной вывозки и перевозки сортиментов автомобильным транспортом.


It has turned 50 years since the short log hauling started to convert into the tree-length one. At that time, it allowed to increase the effectiveness of running the timber enterprises and haulage as well. However,  further development of machinery and technology was being realized mainly to the detriment of timber hauling, which contributed to the impairment of running conditions of timber trains, to the decrease of their dependability and productivity [1].


During the last years lumbering in Russia has undergone serious changes [2], especially in the forests of the European part of the country. It resulted in the further decrease of effectiveness and worsening of  working conditions of the loading-logging system in timber haulage.


The timber hauling phase is the most expensive and power-consuming in the overall structure of lumbering process. That's why further refinement of timber haulage process as well as of process related working operations is essential for rising the qualitative attributes of timber enterprises functioning.


The effective run of timber hauling trains is impossible without the solution of the following basic tasks.


First of all, it is necessary to select the right type of logging timber. In Russia, tree-length hauling technology is the most widely adopted one. However, short log stocking and hauling would be more effective in a number of cases. 25% of wood in the world is stocked by a short log method, while it's about 80 % in Finland and other Scandinavian countries.  The priority of short log method should be given to gradual and selection felling in small wood-cutting areas, as it is more favorable for the environment. The whole-tree hauling causes a worse damage to the forest than small-sized logging machines and logging wheeled vehicles do. The short log haulage gives an opportunity to provide with larger loading and better freight allocation between train units than the tree-length haulage. That's why the problem of short log technology of timber stocking and hauling has become the main priority in Stock Company of Head Scientific Institute of Researches in Mechanization and Energetic' ( SC of HSIRME')  projects. 


Choosing the type of timber for the haulage isn't only an industrial, but also a social problem. At the present time, the short log haulage enterprises have bulky forest depots, where a great number of workers are involved. These depots are located in immediate proximity to settlements or within the precincts of those, which is  very convenient for people. When being involved in short log haulage, the total number of workers are generally decreased, but the part of workers involved in cutting area work are rather increased at the same time. The considerable capacity of the lower timber landing equipment turns out to be left unclaimed.


The type of logging timber in many respects defines the kind and the construction of timber motor trains. Their working conditions are no less important factors, and these conditions might be different. But it practically doesn't influence the selection of a truck-trailer and train units. In the main logging regions, republics and areas, historically one kind of timber train has been used. It is due to the developed production connections with the plant producers, to the simplification of spare parts supply and train repairs. On the other hand, the landscape difference within the region and the diversity of road-ground conditions are not taken into consideration. During the last years, the lack of central supply of enterprises with equipment and the imperfection of their financial possibilities have led to the needless variety of timber trains used at one enterprise. The most widely used and practically the sole type of timber units involved in tree-length haulage is a two-axle timber drag. For the short log hauling and carting SC of HSIRME has designed and produces now two-unit trains TM-45, TM-48, TM-78, TM-79 [3], consisting of a truck and a trailer.  At that, the availability of only two-unit trains and the lack of variety of trailer unit leads to incomplete utilization of train hauling abilities, waste of fuel material and increase of logging related expenses. The advantages of a winter season are not fully used.


The selection of a loading device is a very important task of optimization of loading-logging system work. When working with concentrated forest-cutting areas and long-distance trips,  it is economically approved to use detached loading devices. However, under present-day conditions, when the number of cutting areas developed during a year increases while the quantity of logging timber considerably falls down [2], the range of application of self-loading trains is being enlarged significantly. At that point, it is necessary to accomplish a task of selecting a hydraulic handler and placing it on a mobile unit. Depending on carrying capacity and handler swinging radius, on the type and the size of the carried timber as well as on the train construction, a handler can be placed either behind a driver's cab or in the back of the cab, on a trailer or a semitrailer. Fastening is allowed to be either rigid or with the possibility of lengthwise movement within the trailer or semitrailer frame.


Besides the advantages, the usage of the hydraulic handler for timber train self-loading leads to the necessity of reduction the trip loading by the handler's weight, which causes the rise in fuel rate and drop in productivity. We may try to solve the problem in the following ways. For instance, under certain conditions, it is possible to combine the work of two or several trains, one of which is equipped by a hydraulic crane. The other technique has been tested in Karelia, when a hydraulic handler is installed on a train only for a time of timber being loaded. Immediately after the loading or right before reaching the highway, a driver disassembles the handler and leave it on the side of the road [4]. It gives an opportunity to increase the loading by 2-3 square meters, but on the other hand it makes a train stay longer at the loading point. Besides, the Karelian technique requires a driver to have certain skills. That's why we are working over another variant of running self-loading trains.


At the present time, the enterprises tend to export only one type of roundwood: tree-length, log-length and short log material. Mostly even in short log hauling, their length comes to the same size. It is due to maladjustment of timber-carrying mobile unit and unwillingness to do timber bunching, and it leads to considerable waste of timber in the long run. It sure is advisable to use universal train units which allow to carry short logs of different sizes. For that, it is necessary to equip the train units with the sufficient number of collector bunks as well as to place those on a mobile unit. Increase in the number of collector bunks will make a train unit heavier and reduce actual load. As an alternative, here should be viewed a possibility of moving collector bunks within truck and trailer frames as well as changing their number. The usage of the specialized train units, for instance, in short log hauling, with crosscut placement of timber on a train would allow to provide with larger loading and would increase the productivity.


Our numerous researches have ascertained that the load of collector bunks and shunter in tree-length hauling don't conform to their carrying capacity. In most cases, the collector bunk is essentially overloaded, while the shunter isn't given full load. This situation is even more aggravated in log-length hauling [5]. Lack of loading control and manufacturing culture lead to the overload of train units in short log hauling as well. As a result of the overload, train units fail more often, and high axial load causes deterioration of the roads, which are already in a poor state. In order to make working conditions of timber train units better, it is essential: to select the right way and parameters of placing the carried timber on a train collector bunks; to inform train drivers and loading operators about it and constantly control their work; to equip timber-carrying train units with load monitoring automatic devices. Application of automatic control over loading of means of transport is very actual nowadays, and it may solve the problem of using the overall road system for timber logging freely. At the present time, due to the lack of control over loading most of logging train units, these trains should be considered heavy freight trains as a result of axle load increase, and they should be run according to "Large-size and heavy freight hauling instruction for motor transport". When controlling the means of transport, it will inevitably lead to punitive sanctions. This kind of control is widely used in foreign road systems and it starts to be put in order in Russia.


Concrete resolutions of projects outlined here will be expounded in next publications.




1.       Smirnov M.Y., Gryazin A.D. Study of logging train units working conditions // Exploitation of logging mobile units: Inter-institutional annual of scientific researches/ Ural institute of forest industry.- Sverdlovsk: UPI, 1985. – P. 115-119.

2.       Smirnov M.Y. Self-loading train units in timber logging // scientific conference articles by teaching staff, applicants for doctor's degree, post-graduates and assistants of Mari State University of Technology, May 27-31 1996, 2d edition.- Yoshkar-Ola, 1996.- P. 124-125.

3.       Bolshakov B.M. Some aspects of short log technology. // Forest industry.- 1997. – N 1.- P. 16-18.

4.       Amosov A.A., Vasyukov V.A., Demin Y.A. Finish techniques of cleaning cutting in Karelia // Forest industry.- 1990. – N. 11. – P. 25-26.

5.     Smirnov M.Y., Gryazin A.D., Shirnin Y.A. New techniques of timber logging: Tutorial.- Yoshkar-Ola, Mari Teachers' Training Institute, 1993. – 104 pages.