At Howard, Yellow Line passengers can transfer to the Purple or Red Lines of the "L". The Yellow Line is the only "L" line that does not go to The Loop and is the only "L" train route that is fully ADA accessible. It is also unique in that it runs in a below-grade trench for part of its length, even though it has no underground portions and does not run in an expressway median. It also includes grade segments and crossings at the northern portion of the line. It was built using the tracks of the former Chicago North Shore and Milwaukee Railroad's high-speed Skokie Valley Route.