https://www.youtube.com/watch?v=pphgq49lslI nyc subway on the A line
https://www.youtube.com/watch?v=nxWpFejRAks the A line express
https://www.youtube.com/watch?v=ukOHqdPbYYg the 7 line
https://www.youtube.com/watch?v=fJzhNPKtR0Q CTA brown line
https://www.youtube.com/watch?v=4wXB8htl3Zo Chicago L
https://www.youtube.com/watch?v=7NPCFnF4csA The history of the "L" train lines have always been a fascination of Chicago.
https://www.youtube.com/watch?v=hd-8pBS9IxA Chicago Streetcar & Elevated Lines - 1952 to 1956
https://www.youtube.com/watch?v=trCkptXQc1E old streetcar tunnels
https://www.youtube.com/watch?v=Gwm_0eywrVc old Chicago tunnels
