train delays

A short clip from the 1983 BBC series Fun to Imagine in which Richard Feynman explains how a train stays on the track. He covers the geometry of tapered wheels that steer the train back toward the center of the rails.

A Wendover Productions explainer on why train tickets, especially Amtrak in the US, cost so much compared with flying. It breaks down staffing, speed and the cost components behind a ticket.

An MTA video on communications-based train control, the system meant to replace the New York City subway's century-old signaling. It also shows the mechanical interlocks and signals in use today.

A short clip of Richard Feynman explaining how a train stays on its tracks, through the conical shape of wheels and how it handles curves without differentials.

Not Just Bikes explains why Swiss trains are considered among the best in Europe and the world, covering frequency, connections and what riding them is like.

Yosh trains a reinforcement learning agent to drive Trackmania until he can no longer beat it. The video explains how the training works and the design choices involved.

Wendover Productions explains why US passenger rail lags behind other countries. It covers freight companies owning most of the track, geography and population density, and the economics of competing with flying.

Rick Beato argues that adults cannot develop true perfect pitch, which he ties to critical-period brain plasticity and language acquisition. He says it can only be developed in young children, and discusses the research behind this.

Robert Miles explains reward modelling, in which an AI learns what humans want from their preference comparisons instead of a hand-written reward function. He walks through the 2017 paper on deep reinforcement learning from human preferences.

Martin Donald explains the Wave Function Collapse algorithm using Sudoku-like constraint solving and shows how he implemented it with Blender and Godot. It links demos and reference articles.

FortNine's tongue-in-cheek guide to why drivers fail to see motorcyclists and how riders can make themselves more visible. It touches on perception psychology, including the role of saccades.

Alex O'Connor shows that ChatGPT cannot draw a wine glass filled to the brim, and ties the failure to David Hume's missing shade of blue. It asks what the failure says about how image models learn.

Not Just Bikes examines Toronto's GO Transit commuter rail, arguing it is a costly system with park-and-ride stations and rush-hour-only service that subsidizes car-dependent suburbs.

Tom Scott visits an eHighway test in Lubeck, Germany, where electric trucks with pantographs draw power from overhead wires. He explains how this could electrify road freight.

Adam Neely explains what perfect (absolute) pitch is, how it differs from relative and quasi-absolute pitch, and why he would not want it. He covers its drawbacks, including drift with age.

A Blender-animated explanation of the Toyota Hybrid Synergy Drive, showing how the engine, two motor-generators, planetary gearset and battery work together as an eCVT.

Wendover Productions explains why Amtrak trains run late: most Amtrak routes run on freight-owned track, and the law giving passenger trains priority is rarely enforced. The video covers rail ownership versus control and how freight carriers hold the leverage.

A 3D-animated walkthrough of a heavy-haul diesel-electric freight locomotive, covering the frame, coupling, draft gear, engine and drive systems. Made in Blender by Animagraffs.

PBS Space Time explains the proposal to use the Sun's gravity as a giant lens, sending a train of small light-sail spacecraft to the focal point roughly 550 AU out. It covers how such a telescope could image exoplanets in surprising detail and the engineering challenges involved.

CGP Grey explains how traffic jams come from human driving behavior such as tailgating and reaction delays, and how leaving gaps and smoothing speed would reduce congestion. It also touches on self-driving cars.

Mark Rober makes a plant-based burger for Bill Gates and explains why meat production strains the environment. Gates also appears and discusses his worry about steel and cement.

3Blue1Brown's second neural network chapter explains cost functions and gradient descent, showing how a network learns by minimizing error during training.

AVweb's Paul Bertorelli explains in part two of a series why general aviation has not replaced leaded avgas. He covers industry inertia, bureaucratic delays and the exemption that lets the industry keep using lead.

Matt Parker of Stand-up Maths demonstrates MENACE, Donald Michie's 1961 machine made of matchboxes that learns to play noughts and crosses through reinforcement. He builds and trains a physical version.

A Vox explainer on why California's high-speed rail project is years late and far over budget, with only a few concrete structures built by 2022. It covers the political, legal and routing challenges behind the delays.

Rob Miles explains "glitch" tokens, odd strings in large language model vocabularies that make the model produce gibberish. He covers how they likely arise from tokenizer training data, such as Reddit usernames, that never appeared in the model's own training.

Musician Benn Jordan explains and demonstrates adversarial noise that poison-pills music files against AI training and scraping.

A 1951 Bell System training film showing how telephone calls are routed through a step-by-step (Strowger) switching office.

Technology Connections explains how a home can act as a thermal battery by pre-cooling or pre-heating when electricity is cheap or abundant. He shows how this shifts load off-peak and eases strain on the grid.

A short animated explanation of the power split device in Toyota-style hybrids, a planetary gearset that works as an eCVT. It shows how engine and motor power are combined.

Robert Miles covers a paper where researchers ran real versions of his earlier mesa-optimizer thought experiments. They show inner misalignment, where an AI learns the wrong goal in training and misbehaves when deployed.

Practical Engineering explains how continuous welded rail copes with thermal expansion by restraining it, using the relationship between temperature, stress and strain. The video is part of a series on railways.

A SAAMI-produced training video for firefighters explaining what happens when sporting ammunition burns, including that unchambered cartridges lack the energy to penetrate much. It includes test footage of ammunition in fires.

A short Boeing-supplied clip where the 737 MAX program's chief project engineer explains how the lengthened landing gear of the MAX 10 folds up. It shows the gear model in motion.

PBS Space Time asks whether dark matter could be made of primordial black holes. It walks through the observational constraints that limit this idea.