Complex sentence: Escalators were added but the Grand Hall was finally abandoned in favor of renovated ticketing and waiting room on the ground floor (still in use today), and an underground corridor replaced the overhead walkway with ramps at each platform.
Split into simpler sentences: Escalators were added, but the Grand Hall was finally abandoned in favor of renovated ticketing and a waiting room on the ground floor (still in use today). Also, an underground corridor replaced the overhead walkway, with ramps at each platform.