Where does the old subway tunnel at 4th and Hill streets go?

Back in the day of the Pacific Electric cars, the tunnel ran from beneath the Subway Terminal Building near Pershing Square to Glendale Boulevard near Echo Park, where the trains emerged at the Toluca Yards and rolled to what is now the Burbank Ikea store before returning downtown. The subway closed in 1955. The Bona-venture Hotel sliced into the tunnel 20 years later. Today the Terminal Building and the Toluca Yards house apartments.
Photograph by wikipedia.org