What Happened to the Triple Valve? The Brass Valve That Stopped Trains by Letting the Air Out

#TripleValve #MechanicalHistory #ForgottenTechnology What happened to the **triple valve**, the little cast-metal box under every railroad car that stopped a train by letting the air out? In November 1887 a fifty-car freight train weighing around two million pounds stopped in about two and a half seconds, without a single brakeman on the roof. The reason was George Westinghouse's automatic air brake, and the valve under each car that compared two pressures and decided, all by itself, when to brake. This video explores how the triple valve worked, why it made a burst hose stop the train instead of freeing it, how it survived the violent Burlington brake trials of 1887, why Britain chose the vacuum brake until Armagh, and how the Safety Appliance Act of 1893 finally took brakemen off the roofs. Yet the triple valve never truly vanished. The name disappeared in the 1930s when the AB valve replaced it, but its logic still rides under nearly every freight car in North America, and heritage railways still run real triple valves today. Subscribe for more forgotten machines that quietly ran the world. CHAPTERS 0:00 November 1887: fifty cars, one breath of air 1:25 The Armstrong brake 4:15 A wreck outside Schenectady 7:08 The tunnel in Pittsburgh 10:45 The flaw in straight air 13:49 Three jobs in one valve 19:02 Britain chooses vacuum 22:47 Fifty cars at Burlington 27:01 The air-brake fanatic 30:02 Braketown 33:13 The valve that was replaced 36:29 The speed of air 39:42 Still breathing SOURCES (selection) Prout, A Life of George Westinghouse (1921); Westinghouse Air Brake Tests (1904); ICS Westinghouse Air-Brake Handbook (1913); ASME Landmark #273; FRA (1993); US patents 88,929, 124,404, 124,405, 138,827; NTSB preliminary report on East Palestine (2023). Some details of the first air-brake run (date, engineer's name) differ between accounts; the Vanderbilt "wind" story is a later legend. Full credits for footage, photos and music are in the production credits file. Music: "Consecrated Ground" and "Motions" (CC0, public domain). MORE FROM MY OTHER CHANNEL — LostMotionArchive07 👉 Subscribe:    / @lostmotionarchive07   ▶ What Happened to Mechanical Governors? The Devices That Controlled Engines Before Electronics    • What Happened to Mechanical Governors? The...   ▶ Why Flat Leather Belts Disappeared — The Power Transmission System Every Factory Once Used    • Why Flat Leather Belts Disappeared — The P...   ▶ What Happened to Wooden Gear Teeth? The Wooden Cogs Old Mills Built to Break So Iron Gears Wouldn't    • What Happened to Wooden Gear Teeth? The Wo...   ▶ What Happened to Grease Cups? The Old Lubrication Device Once Found on Nearly Every Machine    • What Happened to Grease Cups? The Old Lubr...   ▶ What Happened to Oil-Ring Bearings? The Loose Metal Ring That Oiled Giant Motors Without a Pump    • What Happened to Oil-Ring Bearings? The Lo...   ▶ What Happened to Cone Pulleys? The Simple Speed Control System Every Old Machine Needed    • What Happened to Cone Pulleys? The Simple ...   ▶ What Happened to Herringbone Gears? The Zigzag Gears So Important They Became Citroën’s Logo    • What Happened to Herringbone Gears? The Zi...   ▶ What Happened to Sperm Whale Oil? The Lubricant Trusted in Watches, Looms, and Locomotives    • What Happened to Sperm Whale Oil? The Lubr...   ▶ What Happened to Rawhide Gears? The Animal-Hide Gears That Ran Quieter Than Steel in Early Machines    • What Happened to Rawhide Gears? The Animal...   ▶ What Happened to Leather Seals? The Cowhide Cup That Made the First Hydraulic Press Actually Work    • What Happened to Leather Seals? The Cowhid...   ▶ What Happened to the Hand Crank? The Starting Handle So Dangerous It Forced Cadillac to Rethink Cars    • What Happened to the Hand Crank? The Start...   ▶ What Happened to Line Shafts? The Factory Power System That Once Ran Entire Industries    • What Happened to Line Shafts? The Factory ...   🔔 More videos every week:    / @lostmotionarchive07   #GeorgeWestinghouse #AirBrake #RailroadHistory #Trains #EngineeringHistory