pneumatic systems like these are so fun, costco used to have big tubes they sent wads of cash and other things through, and of course there are great articles about the old pneumatic postal infrastructure in paris
Jams were a bear. Crews would travel the route of the tube and check air pressure at test points every two blocks where the tube surfaced. When they found a drop in pressure at a test point, they would try to free the stuck canister by injecting extra pressure. If that failed, they would have to dig up the street.[2]
In the early 2000s, parts of the network were repurposed to run fiber optic cable.
[1]https://en.wikipedia.org/wiki/Pneumatic_tube_mail_in_New_Yor... [2]https://hal.archives-ouvertes.fr/hal-01870447/document