"4-8-4+4-8-4" meaning in English

{
  "forms": [
    {
      "form": "4-8-4+4-8-4s",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "4-8-4+4-8-4"
      },
      "expansion": "4-8-4+4-8-4 (plural 4-8-4+4-8-4s)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English reduplicated coordinated pairs",
          "parents": [
            "Reduplicated coordinated pairs",
            "Coordinated pairs",
            "Reduplications",
            "Terms by etymology"
          ],
          "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": [
        "Under the Whyte notation system, a Garratt steam locomotive that is articulated in three parts, with a boiler mounted on the centre frame, and two steam engines mounted in opposite directions on separate frames, one on each end of the boiler, and each engine having a 4-8-4 wheel configuration."
      ],
      "id": "en-4-8-4+4-8-4-en-noun-sd6U8dHp",
      "links": [
        [
          "Garratt",
          "Garratt"
        ],
        [
          "steam locomotive",
          "steam locomotive"
        ],
        [
          "boiler",
          "boiler"
        ],
        [
          "4-8-4",
          "4-8-4"
        ]
      ],
      "wikipedia": [
        "4-8-4+4-8-4"
      ]
    }
  ],
  "word": "4-8-4+4-8-4"
}

{
  "forms": [
    {
      "form": "4-8-4+4-8-4s",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "head": "4-8-4+4-8-4"
      },
      "expansion": "4-8-4+4-8-4 (plural 4-8-4+4-8-4s)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English palindromes",
        "English reduplicated coordinated pairs",
        "English terms spelled with +",
        "English terms spelled with numbers",
        "English words without vowels",
        "Pages with 1 entry",
        "Pages with entries",
        "en:Rail transportation"
      ],
      "glosses": [
        "Under the Whyte notation system, a Garratt steam locomotive that is articulated in three parts, with a boiler mounted on the centre frame, and two steam engines mounted in opposite directions on separate frames, one on each end of the boiler, and each engine having a 4-8-4 wheel configuration."
      ],
      "links": [
        [
          "Garratt",
          "Garratt"
        ],
        [
          "steam locomotive",
          "steam locomotive"
        ],
        [
          "boiler",
          "boiler"
        ],
        [
          "4-8-4",
          "4-8-4"
        ]
      ],
      "wikipedia": [
        "4-8-4+4-8-4"
      ]
    }
  ],
  "word": "4-8-4+4-8-4"
}