WMATA continues to have an escalator problem. The transit agency replaced its first 15-year-old escalators last summer at Foggy Bottom, but this morning, major escalators throughout the system broke down during the morning rush hour. Why? About 700,000 people travel through the Metrorail every day, and such dysfunction creates a nuisance as well as raises safety concerns. The escalators, despite all vaunted improvements, continue to fail at key moments — and when three major stations encounter problems in the same morning, it hurts commuter confidence.