Next stop: Vodafone.
While it's common for phone companies to plaster their names prominently on sports stadiums, Vodafone has gone underground. Earlier this year, the wireless carrier signed a three-year deal with Metro de Madrid, the government-owned subway, which allowed the company to rename the train station in the city's central Puerta del Sol square to Vodafone Sol.
So far, the approach hasn't made a big impression on passengers.
Vodafone's service revenue in Spain in the last quarter dropped 10.6 percent from a year earlier, as the company continues to deal with the country's weak economy, high unemployment rate and increasing competition.
But Vodafone isn't ready to hop off this train.
In fact, in September, the subway system's No. 2 line, which is known as the red line, will be renamed Line 2 Vodafone.
"As part of our brand and image policy, we seized this opportunity in order to get closer to Spanish people," said Pepe Romero, a spokesman for Vodafone Spain.
Vodafone isn't the only mobile company trying a different marketing route with public transit. Last year, the same Sol station was named Estacion Sol Galaxy Note for about a month to advertise Samsung's product. And New York City's Metropolitan Transportation Authority has just approved a policy that allows subway stations to be renamed after corporate sponsors, according to the International Business Times.
Regardless of whether Vodafone's effort pays off, it's all good for the unprofitable Metro de Madrid, which is receiving about 1 million euros ($1.32 million) a year in the agreement.
The subway system is coping with lower revenue as debt-ridden Spaniards ride the metro less often, according to Tobias Zisik, Metro de Madrid's strategic planning director. He said that after the agreement with Vodafone, other companies are trying to strike deals to advertise.