臺灣支線鐵路逐漸卸除貨運及通勤功能而停駛，或改以觀光功能主導，改變營運與設施特質，塑造出新的鐵路形象與經驗。本文以臺北都會區郊山地帶的平溪線為例，主張由支線鐵路鏈結的城鄉關係，雖然已從礦產開採轉變為觀光遊憩，依然具有延展都市化的特徵。作為延展都市化驅動之城鄉關係的移動部署，平溪線支持著多樣的遊憩地景和生活型態。在吸引遊客短暫視線的天燈和貓群，以及襲產觀光化的煤礦遺址外，山林瀑布等自然資源仍能支持慢活風格的遊憩型態。再者，兼有幽靜居處和便利交通的條件，也吸引文創工作者落腳，與當地居民形成新的社區組合。作者主張，延展都市化的格局雖難以逆轉，但虧損的支線鐵路仍有維繫異質地景的作用，值得予以再價值化。

The gradual disengagement of branch railways of Taiwan from their tasks of freight and passenger transport have led to the closure of many, while some have adopted a new function of tourism. This trend has significantly changed the nature of the operation of the railway and the facility itself, further reshaping the image of the railway as well as people’s experiences of it. This study considers the Pingxi Line in the suburban mountain area of the Taipei metropolis, and proposes an urban-rural relationship characterized by extended urbanization and supported through the branch line, revealing the current dominance of recreation and tourism in an area formerly dominated by mining. The Pingxi Line has sustained a wide range of recreational landscape and lifestyles, which is integral to the deployment of extended urbanization. Beyond the sky lanterns and cats that only attract ephemeral tourist gazes, as well as the tourist spots of heritagized mining sites, natural resources such as waterfalls and the mountain itself also sustain a slow, relaxed alternative recreation style to urban sites. Moreover, because villages along the Pingxi Line combine convenient transportation links with peaceful surroundings, they attract cultural and creative workers to settle and mingle with the original residents. The authors argue that while extended urbanization is difficult to reverse, this financially struggling branch line still works to sustain heterogeneous landscape, and is therefore worth revitalization.