# Capacitors and supercapacitors and Rail traction

Energy flows from capacitors and supercapacitors to rail traction; their prices have moved together.

Source page: https://www.materialinsights.org/links/capacitors-and-supercapacitors-and-rail-traction/

[Capacitors and supercapacitors](https://www.materialinsights.org/energy/e_supercaps/) (energy) and [Rail traction](https://www.materialinsights.org/energy/e_rail_traction/) (energy): 2 relationships.

## How they are linked

### 1. Energy flow

*Physical flow · Direct · Capacitors and supercapacitors → Rail traction*

Trams use supercapacitors to run between charging stops.

### 2. Price link: onboard storage

*Cost and price · Weak · Both ways*

Trams and metros use supercapacitors to store braking energy and run short distances without wires. The capacitor proxy correlates at -0.14 monthly with the rail equipment index, so no price link shows; this is a technology link only.

- **-0.14** monthly change correlation
- **-0.27** 12-month change correlation
- **0.14** fitted elasticity

Built from the site data on production routes, energy flows, industry value chains, input-output tables and prices.