Pneumatic tube networks: when cities mailed letters by air pressure

A 6-beat faceless video outline for “Pneumatic tube networks: when cities mailed letters by air pressure” in the Forgotten inventions niche, derived from caption timing of 2 reference videos.

Angles

• Open with the odd payloads (a live cat once rode a New York mail tube) to earn attention honestly
• Explain the physics in one diagram: sealed tube, fan, pressure difference, canister
• City networks at their peak: letters per hour, operators, underground routes
• Why it faded: cost and reality, not a dramatic failure — and where tubes survive today

Beat-by-beat structure

1. Hook (0:00–0:30): strange things people have mailed — including a cat through a tube under New York.
2. How it works (0:30–1:30): a fan creates a pressure difference; the canister rides the air.
3. Peak era (1:30–3:00): city pneumatic post networks moving letters across town in minutes.
4. Bigger dreams (3:00–4:00): pneumatic passenger railway demos and why investors backed off.
5. Decline (4:00–5:30): maintenance cost, trucks and phones, then email; survivors in hospitals and bank drive-thrus.
6. Recap: the idea keeps returning under new names. Original narration only.

Method

yt-dlp VTT captions (manual/uploader only) → timed beat heuristics → editorial topic synthesis (no ASR). Structure only; write original narration.