Servicio de Transportes Eléctricos
Servicio de Transportes Eléctricos de la Ciudad de México (STE'; lit. 'Mexico City Electric Transport Service') is a public transport agency responsible for the operation of all trolleybus and light rail services in Mexico City. As its name implies, its routes use only electrically powered vehicles.
Source: Wikipedia — Servicio de Transportes Eléctricos (CC BY-SA 4.0)