An overhead wire of large cross-section made of copper or a copper alloy and provides the current required for the trolleys of electric vehicle is known as trolley wire.When a flexible wire is suspended horizontally between two pole supports, it would assume the form of catenary. But in case of ... Read More

The method of electric braking of traction motor in which the motor remains connected to the supply line and return the braking energy to the supply system is known as regenerative braking.Figure-1 shows the connection diagram of Behn Eschenburg scheme of regenerative braking. In this scheme, an auxiliary transformer is ... Read More

Consider a parallel RLC circuit shown in the figure, where the resistor R, inductor L and capacitor C are connected in parallel and I (RMS) being the total supply current. In a parallel circuit, the voltage V (RMS) across each of the three elements remain same. Hence, for convenience, the ... Read More

A source of light that is mounted on a lamp column or pole either on the side of the road or within the median to provide illumination is known as street lighting.Street lighting is required along the road to have safer, comfortable, convenient and efficient movement of vehicles at night.Objective ... Read More

The flooding of large surfaces with light through powerful projectors, where the light sources are concentrated into narrow light beams using specific reflectors is known as flood lighting. Flood lighting is an artificial light with high-intensity, broad beam.Purpose of Flood LightingThe flood lighting may be employed for the following purposes ... Read More

A thermal power station or steam power plant is a generating station which converts the heat energy of coal combustion into electrical energy.To achieve overall economy in power generation, the following factors should be considered while selecting a site for a thermal power plant −Supply of Fuel (Coal)The thermal plant ... Read More

The irregularities formed in the given weld metal due to wrong welding process or incorrect welding patterns, etc. are known as welding defects.The following table elaborates the different types of welding defects, their causes, and how to prevent these defects −The irregularities formed in the given weld metal due to ... Read More

Mechanism of Train MovementThe essential mechanism of an electric locomotive is shown in the figure below.Here, the armature of the driving motor has a pinion of the diameter d1 attached to it. The tractive effort at the edge of the pinion is transferred to the driving wheel by means of ... Read More

There are two types of AC system of track electrification −Single-Phase Low-Frequency AC System (15 kV to 25 kV at 16$\frac{2}{3}$ Hz, 25 Hz and 50 Hz)Three-Phase AC System (3.3 kV to 3.6 kV at 16$\frac{2}{3}$ Hz)Single-Phase Low-Frequency AC SystemIn a single-phase low-frequency system of track electrification, an AC voltage ... Read More

The speed-time curve of a main line service is best and most easily replaced by trapezoid. The figure shows the simplified trapezoidal speed-time curve for the main line service.Let, $\mathit{V_{m}}$ = Crest speed in kmph$\alpha$ = Acceleration in kmphps$\beta$ = Retardation in kmphpsT = Total time of run in seconds$\mathit{t_{\mathrm{1}}}$ = ... Read More