# Railway electrification and wireless power

Overhead wires and third rails for trains, and power sent without wires.

Source page: https://www.materialinsights.org/energy/e_rail_wireless/

Transport · Electricity · No. 54

- Transport
- Form: Electricity
 Transport · Electricity · Foundation · Energy

In 2025 a DARPA laser beamed over 800 W of power across 8.6 km of open air, with no wires at all.

Chart: Illustration: Railway electrification and wireless power

##### Where it comes from

Chart: Map of where it comes from

Substations along the track take grid power and feed it to an overhead wire or third rail. A pantograph presses against the wire, so an electric train never carries fuel.

##### Three things to know

1. Optimised timetables let a metro reuse 95.5% of its braking energy, against 80.6% in normal running, in one modelled case.
2. Some UK electrification schemes cost GBP 2-2.5 million per single-track km, against GBP 350,000-450,000 for overhead-line work in Switzerland and Germany.
3. A battery swap takes about five minutes, but a swap station costs about 15 times as much as a fast charger.

##### The journey

1. 1 **Grid**Feeds traction substations along the line
2. 2 **Substation**Supplies the track, often 25 kV AC
3. 3 **Wire or rail**Catenary or third rail carries current
4. 4 **Pantograph**Roof collector feeds the traction motors
5. 5 **Braking**Motors return energy to the line

##### Go deeper pick a tab to open it in full

## Other sections

- [Overview](https://www.materialinsights.org/energy/e_rail_wireless/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_rail_wireless/correlation/index.md)
- [How it works](https://www.materialinsights.org/energy/e_rail_wireless/explain/index.md)
- [Efficiency and losses](https://www.materialinsights.org/energy/e_rail_wireless/efficiency/index.md)
- [Technology advances](https://www.materialinsights.org/energy/e_rail_wireless/advances/index.md)
- [Value chain](https://www.materialinsights.org/energy/e_rail_wireless/valuechain/index.md)
- [Geopolitics and regulation](https://www.materialinsights.org/energy/e_rail_wireless/geopolitics/index.md)
- [Unit economics](https://www.materialinsights.org/energy/e_rail_wireless/economics/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_rail_wireless/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_rail_wireless/links/index.md)