Which of the following is NOT a system of train electrification?
Analysis & Theory
Hydraulic traction is not an electric traction system. The common systems include AC, DC, and composite (AC+DC) systems.
Which voltage is typically used in **DC train electrification** systems in India?
Analysis & Theory
DC traction systems in India commonly use 1500 V or 750 V, especially for suburban or metro networks.
Which of the following is the **standard AC electrification system** used for mainline railways in India?
Analysis & Theory
25 kV, 50 Hz single-phase AC is the standard mainline railway electrification system in India.
What is the advantage of **25 kV AC** over DC electrification systems?
B
Reduced line losses over long distances
C
Requires no substations
D
Higher regenerative braking efficiency
Analysis & Theory
AC systems like 25 kV are suitable for long-distance transmission with lower losses compared to low-voltage DC systems.
Which of the following is true about the **composite train electrification system**?
A
Uses only diesel engines
B
Combines hydraulic and electric traction
C
Uses AC supply with on-board conversion to DC for motors
D
Supplies DC power at the catenary level
Analysis & Theory
In composite systems, the overhead AC is converted to DC using rectifiers or to 3-phase AC using inverters onboard.
Which type of electric traction system is most suitable for **urban metro trains**?
Analysis & Theory
DC systems are preferred for metro and suburban railways due to better acceleration and suitability for short-distance travel.
In a **third rail DC system**, how is power supplied to the train?
B
Using diesel generators
C
Via an extra rail at track level
Analysis & Theory
In a third rail system, a conductor rail runs alongside the track to supply DC power, often used in metros.
Which one of the following is **NOT** an advantage of AC electrification over DC?
A
Reduced transmission loss
B
Fewer substations required
C
Higher efficiency at low speeds
Analysis & Theory
DC systems offer better performance at low speeds, making them suitable for metro trains, whereas AC is preferred for long-distance routes.
Which system requires more frequent substations along the railway line?
B
25 kV AC electrification
C
Diesel-electric traction
Analysis & Theory
DC systems have higher losses and lower voltage, so substations are needed more frequently than in high-voltage AC systems.
In train electrification, why is **single-phase AC** often used instead of three-phase AC?
A
It is easier to generate
B
Motors do not work on 3-phase
C
It reduces complexity of current collection equipment
D
It simplifies substations
Analysis & Theory
Single-phase AC simplifies the overhead wire and current collection systems used in train electrification.