"railbound" meaning in English

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "rail",
        "3": "bound"
      },
      "expansion": "rail + bound",
      "name": "compound"
    }
  ],
  "etymology_text": "From rail + bound.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "railbound (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Rail transportation",
          "orig": "en:Rail transportation",
          "parents": [
            "Transport",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "confined to running on rails."
      ],
      "id": "en-railbound-en-adj-s~M-po4E",
      "links": [
        [
          "rail transport",
          "rail transport"
        ]
      ],
      "raw_glosses": [
        "(rail transport) confined to running on rails."
      ],
      "tags": [
        "not-comparable"
      ],
      "topics": [
        "rail-transport",
        "railways",
        "transport"
      ]
    }
  ],
  "word": "railbound"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "en",
        "2": "rail",
        "3": "bound"
      },
      "expansion": "rail + bound",
      "name": "compound"
    }
  ],
  "etymology_text": "From rail + bound.",
  "head_templates": [
    {
      "args": {
        "1": "-"
      },
      "expansion": "railbound (not comparable)",
      "name": "en-adj"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "adj",
  "senses": [
    {
      "categories": [
        "English adjectives",
        "English compound terms",
        "English entries with incorrect language header",
        "English lemmas",
        "English uncomparable adjectives",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Rail transportation"
      ],
      "glosses": [
        "confined to running on rails."
      ],
      "links": [
        [
          "rail transport",
          "rail transport"
        ]
      ],
      "raw_glosses": [
        "(rail transport) confined to running on rails."
      ],
      "tags": [
        "not-comparable"
      ],
      "topics": [
        "rail-transport",
        "railways",
        "transport"
      ]
    }
  ],
  "word": "railbound"
}