An increase in the volume of goods transported and the intensity of train traffic along the main transport routes led to the emergence of electrified railways. Such objects are quite difficult to implement technically. Unlike the first electrified railways, modern highways are engineering infrastructure complex from an engineering point of view and fulfill a number of important tasks for the population and the state economy. This article describes the history of the emergence and development of electric-powered railway transport, gives basic technical characteristics and an idea of the substation system and the locomotive fleet.
The early history of the electrified railway
The first electric locomotive in its history owes its appearance to the world famous German inventor and businessman Werner Siemens. This model was presented to the whole world at the exhibition of achievements of industry and science in Berlin on May 31, 1879. An electrified railway with a contact network was built specifically to demonstrate the capabilities of an electric locomotive. The length of this experimental path was a little over 300 meters. The device, which was demonstrated to the public, by modern standards can hardly be attributed to locomotives. Rather, it was his model. The vehicle weighed only 250 kilograms, had a capacity of three horsepower and could reach a speed of no more than 7 kilometers per hour. An additional rail was used to supply voltage. The rolling stock consisted of three cars. In total, they could accommodate no more than 18 people.
Such a novelty aroused great interest from business representatives. Already in the same 1879, a road 2 km long was built to deliver workers and raw materials on the territory of one of the French sewing factories.
Thus, initially electric-powered rail transport was used at industrial enterprises and for the transportation of passengers within the city (tram lines). However, after only a few years, traffic along the route Likterfelzh - Berlin opens. The grand opening with the cutting of the red ribbon took place on May 16, 1881.
Electrification of railways in Soviet Russia and the USSR
In tsarist Russia, due attention was not paid to the development of electric railway transport. In large cities, tram lines were built. The main railways connecting the largest cities of the empire were not electrified. In 1880, a scientist by the name of Pirotsky managed to budge a heavy railroad car with electricity. But this experiment did not interest anyone. Only with the advent of Soviet power did the discussion of the prospects for the development of this industry begin. At that time, electric-powered locomotives were actively introduced in most countries of the world. Electrified railways were simply vital to develop. Already in 1921, a strategic plan for the electrification of all territories of the country was approved. In accordance with the announced plan, the contact network of electrified railways was supposed to stretch over the most important highways that connect large industrial regions and cities.
Already in 1926, a twenty-kilometer stretch of road with a contact electric network was put into operation. He connected the capital of the Azerbaijan SSR with the oil fields of Surakhani. In this area, a direct current voltage of 1200 volts was used. The year 1929 was marked by the inauguration of the first train from Moscow to Mytishchi. These events marked, without exaggeration, the beginning of a new era in the history of the development and industrialization of our country.
After several decades, alternating current is replaced by alternating current. On December 19, 1955, the Mikhailov-Ozherelye railway section was commissioned. Its length is 85 kilometers. Locomotives in this section were supplied with alternating current of industrial frequency (50 Hertz) with a voltage of 22,000 volts. A year later, the contact power lines were extended to Pavelets 1. Thus, the total length of this route was about 140 kilometers.
General information about the railway of Russia
The railway of the Russian Federation is a huge organism. It is divided into 17 separate departments. According to recent data, the total length of roads in operation reaches 86 thousand kilometers. At the same time, the length of electrified railways is just over half of this value (51%). Not every country can boast of such an indicator. It should be noted that the share of electrified railways in Russia accounts for more than eighty percent of the total cargo and passenger traffic. This is quite understandable. After all, first of all, highly loaded highways are electrified. Moreover, electrification of roads with low traffic is not economically feasible and will incur losses. Such indicators can only be achieved by the united work of the whole people. At the same time, it is necessary to have a very developed mechanical engineering and instrument engineering, a developed electrical industry and scientific potential.
The total length of electrified sections of the railway in our country is approximately 43 thousand kilometers. At the same time, 18 thousand kilometers are powered by direct current. Accordingly, the remaining 25 thousand kilometers operate on alternating current.
Benefits of Electrification
Against the background of a huge number of advantages and advantages of electrified railways, all the disadvantages are simply lost. Firstly, the amount of harmful emissions is much less than from diesel locomotives. This has a positive effect on the environment. Secondly, the efficiency of a locomotive on electric traction is much greater. Thus, the cost of transportation of goods is reduced.
Among other things, electrified railways solve the problem of providing electricity to industrial enterprises and settlements that are located along the railway and not far from it. According to statistics for 1975, more than half of all electricity in the USSR railway contact network was spent on powering these facilities that are not part of the transport infrastructure.
And this is not an exhaustive list of benefits. It should also be said that the electrified railway has a significantly greater throughput, reliability, and creates comfortable conditions for the transport of passengers.
Traction Substations: General Concepts
If you simplify it to a minimum, then traction substation can be given the following definition: installation designed for the distribution and conversion of electricity. In other words, a traction substation is a step-down transformer. If the locomotive operates on direct current, then the substation performs the function of a rectifier. For networks of electrified AC roads, it is necessary to equip traction substations at a distance of 50 to 80 kilometers along the entire stretch of the track. Switching to direct current requires the construction of substations every 15-20 kilometers. In some exceptional cases, this distance can be reduced to 5 kilometers (on especially busy highways).
The metro uses a special type of traction substations. Devices of this type do not convert the variable to constant, but only lower the DC voltage.
Design of traction substation blocks
Traction substation blocks are a complex of cells, panels and cabinets. These elements are mounted on frames and connected by a network of wires (both power and control wires).
There are two types of blocks. In some blocks, all elements are mounted on the frame, in others, each element is placed in an airtight container. Blocks of the first type are intended for installation in buildings. Blocks of the second type are installed along the line of the railway in the open.
Contact network
The contact network is a very complex engineering structure. It includes many elements: the wire itself, the cable (bearing), power poles, rigid and flexible crossbars ... Very stringent requirements are imposed on the suspension. If it does not correspond to them, then the removal of current will occur intermittently, which will not allow the locomotive to work in normal mode and can lead to an emergency. The height and tension of the wire, the maximum allowable curvature, the span and so on are strictly regulated. In our country, locomotives operate simultaneously both on direct current and on alternating current. This, of course, makes electricity supply to electrified railways somewhat more difficult. Each of these systems has its advantages and disadvantages.
Simple contact suspension design
In fact, a simple contact suspension is a wire mounted on supports. The distance between these supports is usually 30-40 meters. Such a design is acceptable only on sections of roads where traffic with high speed is not allowed (bridges, tunnels), as well as in trolleybus and tram power lines.
DC Advantages
Compared to an AC contact network, a DC contact network has a number of advantages. Among them, the opportunity to use it for locomotives with a relatively simple structure and low mass should be specifically abolished. In addition, in such systems there is no effect of the voltage applied to the contact network. The most important benefit is a higher level of operational safety compared to alternating current systems.
Disadvantages of a direct current contact network
The main disadvantage of such power supply systems for electrified railways is their high cost. Indeed, for their construction requires a more complex and expensive suspension. The copper traction wire has a much larger cross section, which also significantly increases the overall cost of the project. An important drawback is the relatively small distance between traction substations on electrified railways in comparison with contact networks for alternating current. On average, it ranges from 15 (in areas with the maximum intensity of trains) to 20 kilometers. Among other things, direct currents cause the appearance of so-called stray currents, which lead to the emergence and rapid corrosion destruction of steel structures and supports.
Requirements for the training of personnel servicing power supply systems
Before an employee is allowed to carry out repairs and maintenance of transmission lines of an electrified railway, he must undergo special training. And this applies not only to people who work directly with the electrical part, but also to fitters and installers who service the entire construction of transmission lines and their supports. All personnel are required to pass a knowledge test and confirm the qualification level.
Conclusion
The emergence of electrified railways marked a rapid growth of industry due to increased traffic and increased cargo turnover. There was an opportunity to significantly increase the mass of goods transported by one locomotive.
In addition, it allowed to solve a number of problems. So, ordinary diesel locomotives at low temperatures often fail. An electric locomotive works reliably in all weather conditions. This, in turn, created the prerequisites for the active development of the northern and Far Eastern regions of our country.