Rail Electrification Systems - Learn EVERYTHING About Them!

Summary

This video from Railways Explained offers an insightful overview of railway electrification systems, highlighting their evolution, types, and the reasons behind their diversity. It discusses the early beginnings with galvanic cells to the adoption of AC and DC systems, and the impact of electrification on train performance and the environment. The script also touches on the challenges of overhead lines and the emergence of multi-voltage locomotives for cross-border traffic, emphasizing the importance of electrification in modern rail transport.

Takeaways

• 🚂 The history of railway electrification began with the creation of the first electric locomotive in 1837 by Robert Davidson, but it was limited by the power of galvanic cells.
• 🌐 The first electric passenger train was presented by Werner von Siemens in 1879 at the Berlin Industrial Exposition.
• 🔌 Electrification development was slow due to the need to meet unique railway requirements and the lack of general electrification for households and industry.
• 🛤️ After WWI, electrification improved with the advent of large power plants and overhead power lines for high-power transmission.
• 💡 The basic electrification system includes a power supply system for the train's electric motor, with the rail track serving as a return connection for the electrical circuit.
• 🔋 There are various railway electrification systems, differing due to continuous improvements and the timing of electrification in different countries.
• 📊 European and international standards recognize six standard voltage systems for railway electrification, including both direct current (DC) and alternating current (AC).
• 🌍 The variety of systems in Europe is due to independent development within national borders and the principle of interoperability in European transport policy.
• ⚙️ The choice of AC over DC came with the development of suitable high-voltage insulating materials and the ability to use higher frequencies without overheating issues.
• 🚆 The adoption of 25 kV 50 Hz as a standard was based on the efficiency of power transmission and cost, providing an optimal balance between the two.
• 🌐 The need for multi-voltage locomotives arose from the liberalization of cross-border freight traffic and the variety of electrification systems in Europe.
• 🔌 The power supply for moving trains is facilitated by traction or feeder substations that convert electric power to the appropriate voltage, current type, and frequency for the railway.
• 🚆 Overhead lines, or catenary systems, are crucial for supplying electric traction vehicles with necessary energy under all conditions, and are irreplaceable in electrified railways.

Q & A

What was the first known primitive electric locomotive powered by galvanic cells built by?

The first known primitive electric locomotive powered by galvanic cells was built in 1837 by chemist Robert Davidson.

Who presented the first electric passenger train and when was it presented?

Werner von Siemens presented the first electric passenger train at the Berlin Industrial Exposition in 1879.

Why was the development of railway electrification slow before the First World War?

The development was slow because electric traction had yet to meet the unique requirements of railway traffic, and there was insufficient general electrification for households and industry. Additionally, steam traction had reached a high level of development that met the transport demand.

What are the two main types of current used in railway electrification systems?

The two main types of current used are Direct Current (DC) and Alternating Current (AC).

What are the advantages of using AC over DC in railway electrification?

AC allows for the use of asynchronous traction motors, which do not have the issues with high-frequency current that early DC systems faced. AC systems also enable higher train speeds, reduce the number of required substations, and are more efficient for power transmission over long distances.

What is the significance of the 15 kV and 16.7 Hz electrification system in railway history?

The 15 kV and 16.7 Hz system was the first AC system that allowed for the electrification of railways on a massive scale, starting with a locomotive built in Switzerland in 1905.

Why was the 25 kV 50 Hz system adopted as the standard in France?

The 25 kV 50 Hz system was adopted as the standard in France because it represented an optimal balance between efficiency of power transmission and the cost of high-voltage equipment.

What is a pantograph and what is its role in railway electrification?

A pantograph is a device used by trains to collect the required current from the overhead line system by pressing against the underside of the contact wire.

Why are overhead lines more efficient than third rail systems for electrified railways?

Overhead lines are more efficient because they allow for higher train speeds, reduce the number of required substations, and are safer for trespassers and track workers. They also enable more reliable and uninterrupted power supply to the train.

What are the challenges associated with maintaining overhead lines in electrified railways?

Challenges include weather impacts such as fast winds, heavy snow, and rain that can cause traffic disruptions, as well as the need for regular maintenance to prevent wear and ensure reliable power supply.

How does the introduction of multi-voltage locomotives and EMUs address the issue of different electrification systems in Europe?

Multi-voltage locomotives and EMUs are equipped to operate under various voltages, allowing them to travel across different countries with varying electrification systems without needing to change locomotives.

What is a 'neutral section' in the context of electrified railways and why is it used?

A 'neutral section' is an electrically separated portion of the overhead line that allows for maintenance and repair of faults without turning off the entire system. It can be a complete switched neutral section or a short length of non-conducting material.

What are some of the environmental benefits of electrified railways over steam or diesel trains?

Electrified railways reduce environmental pollution, enable more comfortable, quieter, and faster trains, and are generally more energy-efficient, even if the electricity is produced by fossil fuels.

What alternative to electrification has been introduced as a potential 'green solution' for railways with low traffic?

Hydrogen-powered trains have been introduced as a potential 'green solution' for railways with low traffic, as they do not require the extensive infrastructure of electrification and can be more cost-effective in such scenarios.