"slow speed control" meaning in English

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      "expansion": "slow speed control",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
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          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
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          "langcode": "en",
          "name": "Rail transportation",
          "orig": "en:Rail transportation",
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            "All topics",
            "Fundamental"
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      ],
      "examples": [
        {
          "ref": "2020 December 16, David Clough, “Class 37s at 60: the great survivors”, in Rail, page 56, photo caption",
          "text": "Slow-speed control was fitted to Class 37/7s in South Wales, to permit diagramming on the coal circuits between pit and power station.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "An electronic device fitted to locomotives which enables them to operate at a very slow speed when their train is loaded or unloaded on the move."
      ],
      "id": "en-slow_speed_control-en-noun-a7DxSBo~",
      "links": [
        [
          "rail transport",
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      ],
      "raw_glosses": [
        "(rail transport) An electronic device fitted to locomotives which enables them to operate at a very slow speed when their train is loaded or unloaded on the move."
      ],
      "topics": [
        "rail-transport",
        "railways",
        "transport"
      ]
    }
  ],
  "word": "slow speed control"
}

{
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      "expansion": "slow speed control",
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  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
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        "English lemmas",
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      ],
      "examples": [
        {
          "ref": "2020 December 16, David Clough, “Class 37s at 60: the great survivors”, in Rail, page 56, photo caption",
          "text": "Slow-speed control was fitted to Class 37/7s in South Wales, to permit diagramming on the coal circuits between pit and power station.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "An electronic device fitted to locomotives which enables them to operate at a very slow speed when their train is loaded or unloaded on the move."
      ],
      "links": [
        [
          "rail transport",
          "rail transport"
        ]
      ],
      "raw_glosses": [
        "(rail transport) An electronic device fitted to locomotives which enables them to operate at a very slow speed when their train is loaded or unloaded on the move."
      ],
      "topics": [
        "rail-transport",
        "railways",
        "transport"
      ]
    }
  ],
  "word": "slow speed control"
}