Marmaray runs a total of 216 trips per day with 10-minute intervals, said Karaman. "Travel was free of charge for the first 15 days, and it was a very busy period. Today we carry around 80 thousand people a day, and the number keeps increasing. We are working intensively to make sure that there are no hitches or breakdowns, and people can travel comfortably." Karaman said that the busiest station is Sirkeci, serving over 20 thousand people a day. Defining Marmaray as "an underground world", Karaman said Marmaray is a project of very intense labor and efforts. "Therefore, we are pleased with the level of interest," Karaman said. Over 6,5 million passengers have traveled on Marmaray since the railway tunnel opened on October 29.