Introduction
Electricity is used to eliminate smoke and take advantage of the hig efficency of electric motors; however, the cost of railway electrification is very significant in terms of installation and subsequent maintenance for this reason only heavily used lines are electrified.
The electric traction is more efficient with respect the use of diesel oil, less polluting, is not inflamable and doesn’t produce noise.
DC and AC Current
The electrification line has two main difference,DC current or AC current.
Direct Current (DC) locomotives typically at relatively low voltage ( 600 to 3000 volts ). The currents involved are very high therefore particular attention must be paid to the loss of loads along the line and the whole electrical system must be able to dissipate all the power.
Alternate Current (AC) has an higher voltage with respect the DC current, the higher the voltage, the lower is the current for the same power and the power loss is much more less than DC.
Main role of a Must
The main task of a pole is to secure the position of the catenary, infact the catenary runs in a predefinited path above the track in order to garantee good electrical contact with the pantograph as well as minimize the wearing.
This is usually implemented at the design phase by establishing the location of the contact wire at each registration arm (pole/mast), in other words, its height (over the top of rail plane) and stagger (the zig-zag distance from the track axis).In order to reduce the wear on the wearing surface of the pantograph every overhead line is arranged in a continuous zig-zag curve within given limits relative to the centre of the track.
Numbering of OHL Pole
The OHL poles are used to indicate the kilometerage of the track. The pole number is also used for identification of the section of overhead equipment and the line to which it belongs. There are normally 15 to 18 poles in one kilometer and each pole is given a number in serial order starting from kilometer post. The number is described in two parts, the kilometer being shown above the line and the pole serial number below the line.
(Km)/(Pole SerialNumber)
For example, (70/1) indicates the first pole from the kilometer post No. 70 on the Up line.
In Single Line Section where there is no chance of future doubling, numbering is done progressively in the direction of increase of kilometerage, i.e. 70/1, 70/2,etc.
In Double Line Section all traction pole on Up track shall be given odd numbers, i.e. 70/01,70/03, 70/05 etc. and that on Down track even numbers as 70/02, 70/04, 70/06,etc. 1 and 2 are the serial number of the poles immediately after every kilometer post. Numbering is done progressively in the direction of increase of kilometerage.
In case the spans on the Up and down lines are not equal and the poles are not in one line, the poles shall be numbered in such a way that higher serial number does not occur at a lower kilometerage.
Conclusion
Finally, it is possible to conclude that electric locomotives playing a vital role in railways sysem till now. Electricity is used to eliminate smoke and take advantage of the high efficiency of electric motors;
