De qué está hecho metro
An urban railway separated from the streets; the first was in London.
- Torniquete de acceso — tiene como parte. Turnstiles.
- Locomotora eléctrica — utiliza. The first lines were steam-operated; electric trains since 1890.
- Vía férrea — utiliza. It runs on rails.
- Escudo de túnel — utiliza. Metro tunnels were built with shields.
- Túnel — utiliza. Tunnels.
- Ladrillo — está hecho de. The vaults of the first tunnels are brick.