Subway
A subway was an underground form of public railroad transportation in many Earth cities in the 20th and 21st centuries, consisting of trains passing through tunnels which linked numerous stations throughout the system together. 

Passengers would hang onto handles on the trains in order to keep their balance.  freighters had similar handles for the same reasons. ()

In an alternate version of 1944, Carmine offered Alicia Travers a hamburger near the closed off Sixth Avenue subway station. ()

In 1968, Roberta Lincoln told Gary Seven she was late for work because the subway was stalled. ()

Upon materializing in the San Francisco of 2024 due to a transporter malfunction, Jadzia Dax was found outside of a subway station. ()

The holographic Keystone City featured a subway station. ()

In the 24th century, San Francisco's main public transportation system was called Trans Francisco. ()

External link
 
Infrastructure