Some　cities＇　subways　were　constructed　early　and　have　been　in　operation　for　a　long　time.　A　large　amount　of　heat　accumulates　in　the　rocks　around　the　subway　tunnels,　causing　the　phenomenon　of　heat　accumulation.　This　situation　leads　to　the　inadequate　cooling　capability　of　train　air-conditioning　systems,　which,　may　even　cease　to　function　under　extreme　conditions.　Currently,　few　solutions　are　available　to　address　this　issue.　Therefore,　this　study　proposes　a　new　cooling　system　in　subway　tunnel.　Considering　the　dusty　environment　inside　the　tunnel,　the　terminal　equipment　mainly　consists　of　natural　convection　copper　tube　finless　heat　exchangers　and　a　self-flushing　device　without　fans,　which　cool　using　piston　wind.　By　comparing　field　measurements　of　two　tunnels　with　and　without　the　cooling　system　in　similar　locations,　the　results　show　that　the　air　temperature　in　the　tunnels　is　reduced　after　the　cooling　system　is　installed.　The　results　indicate　that　the　average　temperature　in　the　tunnels　decreases　from　30.93　°C　to　19.80　°C,　marking　a　reduction　of　11.13　°C　after　the　cooling　system　runs　for　24　hours.　The　temperature　change　in　the　tunnel　is　a　long-term　process,　and　actual　measurements　require　significant　time　consumption.　In　this　study,　the　long-term　effect　is　predicted　using　CFD　simulation　in　tunnels.　The　accuracy　and　credibility　of　the　CFD　simulation　have　been　confirmed　through　its　reasonable　agreement　with　experimental　data,　with　the　final　temperature　after　24　hours　achieving　a　relative　error　of　less　than　0.26%.　Through　the　simulation,　the　temperature　at　a　depth　of　10　cm　inside　the　tunnel　wall　after　24　hours　is　determined　to　be　27.56　°C,　indicating　a　reduction　of　3.44　°C　compared　to　the　initial　temperature　of　31　°C.　This　study　can　provide　a　reference　for　other　subway　tunnel　cooling　systems　and　serves　as　a　basis　for　CFD　simulations　to　verify　cooling　effects.　©　Published　under　licence　by　IOP　Publishing　Ltd.