Since 2013, there has been a series of large investments on the network, with all lines (with the exception of the Urquiza Line) receiving new rolling stock, along with widespread infrastructure improvements, track replacement, electrification work, refurbishments of stations and building entirely new stations. Similarly, almost all level crossings have been replaced by underpasses and overpasses in the city, with plans to replace all of them in the near future. One of the most major projects under way is the electrification of the remaining segments of the Roca Line – the most widely used in the network – and also moving the entire section of the Sarmiento Line which runs through the heart of the city's underground to allow for better frequencies on the line and reduce congestion above ground.