Railway Electrification Voltages 

By on

This post is quick introduction and overview to different railway electrification voltages used in answer to a question sent in via email.

While there are numerous voltages in use through out the world (many dating back a hundred years), fortunately the number of voltages levels in common/widespread use is relatively few. To keep the post short, I will only list the more common voltages.

Both dc and ac systems are used. Direct current systems are generally used for metro lines and relatively commuter /regional systems up to around 100 km long. For longer and more heavily loaded routes, alternating current is generally used.

Direct Current (dc) Voltages

Most commonly used are 600/650 and 750 V. These are used world wide on mass transit, commuter and tram lines. Voltage is supplied to the train using a third rail or overhead lines.

1.5 kV (typically supplied overhead) is used in Europe, the US, China, Australia and a several other countries. Less common are 3 kV systems, but these can still be found in operation in several countries.

Alternating Current (ac) Voltages

25 kV (50 Hz or 60 Hz) ac systems have achieved widespread use in many countries, including the UK, US, large parts of Europe, Asia, Africa and the Americas. Additionally 15 kV (16 2/3 Hz) networks still have widespread use within Europe and the US still has several 12 kV (25 Hz) lines.

The US, South Africa and Canada also operate 50 kV systems in operation (typically used on systems for mine haulage).

It would be fair to say that 25 kV has become the international standard. This is covered by two standards:

  • BS EN 50163 - Railway applications. Supply voltages of traction systems
  • IEC 60850 - Railway Applications. Supply voltages of traction systems

Alternating current systems invariably are supplied by overhead lines. It is worth noting that most implementations are single phase (due to problems with picking up three phases from the overhead lines).  

That's it; a quick summary. It doesn't cover every voltage, but hopefully will give everyone a general understanding of the most common voltages used.

If anyone has anything to add or want to give a few more details, please do so below.



Steven McFadyen's avatar Steven McFadyen

Steven has over twenty five years experience working on some of the largest construction projects. He has a deep technical understanding of electrical engineering and is keen to share this knowledge. About the author

myElectrical Engineering

comments powered by Disqus



Cost Performance and Time

Often us engineers get so bogged down in equations, using software, producing drawings and writing specifications that this becomes the sole focus.   ...

Resistors

Resistors are electronic components that oppose the flow of current.  Manufactured in various types and ranges they have a wide application to electronics...

Cable Insulation Properties

Cable insulation is used to provide electrical separation between conductors of  a cable.  During the historical development of cables, numerous types...

Lead us, Warleader

Delum, who had watched all in silence, his face empty of expression, now spoke in turn. ' "Lead us, Warleader, into glory."' Reading is something I do...

Closed Doors

"I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers that might be wrong...

EU Code of Conduct on Data Centres - Best Practices

The European Union is implementing a voluntary code of practice for participants with the aim of improving the overall efficiency of data centres. As part...

Electrical Engineering

Electrical engineering is a field that covers a wide variety of sub-fields, including electricity and electronics. It is a field that goes back to the...

Tech Topics/Application Notes - Siemens

There are a lot of interesting two page type notes on various medium voltage topics – switchgear, circuit breakers, bus systems etc. It is on the Siemens...

Operational Amplifier

The fundamental component of any analogue computer is the operational amplifier, or op amp. An operational amplifier (often called an op-amp,) is a high...

UPS - Uninterruptible Power Supply

A UPS is an uninterruptible power supply.  It is a device which maintains a continuous supply of electrical power, even in the event of failure of the...

Have some knowledge to share

If you have some expert knowledge or experience, why not consider sharing this with our community.  

By writing an electrical note, you will be educating our users and at the same time promoting your expertise within the engineering community.

To get started and understand our policy, you can read our How to Write an Electrical Note