Why do tram and metro networks have lower driving speeds and axle loads compared to regular trains?

• They are built for high-speed travel.

• They have more powerful engines.

• They follow city streets with sharp turns.

• They are designed for longer distances.

Answer explanation

Tram and metro networks operate in urban environments, often following city streets with sharp turns. This necessitates lower driving speeds and axle loads to ensure safety and maneuverability, unlike regular trains designed for straight tracks.

What is the purpose of canting tracks in railway systems?

• To make tracks more visible.

• To limit the angle of attack and prevent derailment.

• To reduce the number of carriages.

• To increase the speed of trains.

Answer explanation

Canting tracks, or banking, helps limit the angle of attack for trains on curves, reducing the risk of derailment by counteracting centrifugal forces. This design enhances safety and stability during high-speed travel.

Why is it difficult to add a switch within a canting track?

• Switches increase the speed of trains.

• Switches require a different type of rail material.

• Switches are not compatible with modern bogies.

• Switches need to connect tracks that are on one level.

Answer explanation

Switches need to connect tracks that are on one level because they facilitate the smooth transition of trains from one track to another. In a canting track, the elevation changes make it challenging to maintain this level connection.

What is the function of suspension in modern bogies?

• To reduce the number of carriages.

• To dampen the ‘hunting’ behaviour of the train.

• To enhance the train's fuel efficiency.

• To increase the speed of the train.

Answer explanation

The function of suspension in modern bogies is primarily to dampen the ‘hunting’ behaviour of the train, which helps maintain stability and comfort during travel, rather than reducing carriages or enhancing fuel efficiency.

What happens to a train traveling over a wavy surface at high speed?

• It follows the wavy structure closely.

• It derails immediately.

• It only makes contact with the top of the waves.

• It stops automatically.

Answer explanation

At high speed, a train on a wavy surface tends to only make contact with the peaks of the waves, rather than following the contours closely or derailing, as the inertia keeps it stable on the track.

Why is maintaining a straight track over time highly expensive?

• Because of the high cost of rail materials.

• Due to the need for frequent train stops.

• Because the rail slowly transforms into a wavy surface.

• Due to the high speed of trains.

Answer explanation

Maintaining a straight track is costly because over time, the rail can deform, creating a wavy surface. This requires regular maintenance to ensure safety and efficiency, making it an expensive ongoing process.

What is the effect of a train passing over welded track sections?

• The train stops automatically.

• The rails vibrate due to the load.

• The rails become more rigid.

• The train speeds up.

Answer explanation

When a train passes over welded track sections, the load causes the rails to vibrate. This vibration is a result of the dynamic forces exerted by the train, making 'The rails vibrate due to the load' the correct choice.

How is the vibration of rails compared to a guitar string?

• Rails vibrate less than a guitar string.

• Rails vibrate exactly like a guitar string.

• Rails vibrate more than a guitar string.

• Rails do not vibrate at all.

Answer explanation

Rails vibrate less than a guitar string because they are typically made of heavier materials and are designed to be more rigid, resulting in lower frequency vibrations compared to the lighter, more flexible guitar strings.

What happens when heavy rail infrastructure is used for light rail vehicles?

• It improves the train's speed.

• It worsens the vibration due to the relatively light train.

• It reduces the train's fuel efficiency.

• It makes the train more stable.

Answer explanation

Using heavy rail infrastructure for light rail vehicles can lead to worsened vibrations. The lighter weight of the train does not match the heavier infrastructure, causing instability and increased vibration during operation.

What is the comparison made between a fly and a light rail vehicle?

• A fly is heavier than a light rail vehicle.

• A fly is more stable than a light rail vehicle.

• A fly trying to walk over a guitar string is like a light rail vehicle on heavy rails.

• A fly moves faster than a light rail vehicle.

Answer explanation

The correct choice compares a fly's movement on a guitar string to a light rail vehicle on heavy rails, highlighting the challenges both face in their respective environments, rather than making a direct comparison of speed or weight.