{
  "id": "travel-through-time",
  "version": "philadelphia-new-york-three-eras-v1",
  "sourceUrls": [
    "https://www.trentonhistory.org/His/transportation.html",
    "https://americanhistory.si.edu/press/fact-sheets/landmark-object-john-bull-locomotive",
    "https://content.amtrak.com/content/timetable/Acela.pdf",
    "https://www.loc.gov/item/01021358/"
  ],
  "retrievedAt": "2026-10-04",
  "sourceRelease": "1766 advertised service / 1830s Smithsonian benchmark / September30,2026 Amtrak2150",
  "licenseReference": "Original MapifyStats synthesis of factual timings and hand-authored corridor diagrams; source images, prose, logos and protected timetable layout are excluded. LoC1849 guide is public domain.",
  "commercialStatus": "approved",
  "exportStatus": "approved-with-source-attribution",
  "attribution": "Timings: Pennsylvania Journal1766 (Trenton Historical Society transcription), Smithsonian John Bull benchmark, Amtrak2150 Sep30,2026. Diagram and arithmetic: MapifyStats.",
  "bounds": [
    -75.35,
    39.8,
    -73.85,
    40.9
  ],
  "time": {
    "kind": "snapshot",
    "epochs": [
      1766,
      1834,
      2026
    ],
    "unit": "year"
  },
  "units": {
    "travel": "elapsed minutes",
    "summary": "elapsed hours",
    "coordinates": "longitude, latitude degrees"
  },
  "limitations": [
    "Three specific corridor models, not a global speed surface or a complete transport network.",
    "Travel durations come from advertised or institutional benchmarks and one dated modern timetable. Their different precision is labeled.",
    "Historical terminals and modern stations differ. The comparison is between cities, excluding access and boarding costs.",
    "Moving dots illustrate progress along sourced corridors; intermediate historical arrival positions are not observations.",
    "The summer/winter control changes only the documented1766 stagecoach variant. The other models retain their dated or aggregate benchmark.",
    "Reverse journeys, arbitrary destinations and missing service dates are unsupported rather than assigned a uniform speed."
  ],
  "editorialSource": {
    "path": "scripts/animated/travel-source.json",
    "sha256": "3208ce680442b463d5d896ecde0dd3202237c2c3cea667ab1eeb801f8e50b126",
    "bytes": 8666
  },
  "assets": [
    {
      "path": "scene.json",
      "sha256": "73a86b32e7316afad1b18be4dd093cfdcece3c2af5d403f75a9c78849ac27306",
      "bytes": 7892
    }
  ],
  "ingestionCommand": "node scripts/animated/ingest-travel.mjs --check"
}