Chiltern Tunnel South Portal

The route leaves the Colne Valley Viaduct on the West Hyde embankment and enters the Tilehouse Lane cutting before entering the 10.6 mile long twin bore Chiltern Tunnel passing under the M25. The tunnel construction compound is accessed via two temporary slip roads to the M25. Tilehouse Lane has been re-aligned over a new overbridge. Chalfont Lane is closed for at least five years and a temporary link road connects to Hornhill Road. Five PRoWs will be closed for the duration of the construction period.
Two specially designed tunnel boring machines (TBMs) began work in May 2021. Slurry removed from the tunnel is treated and used for landscaping and construction of the West Hyde embankment. The concrete batching plant provides concrete for the Colne Valley viaduct, the Chiltern Tunnel and the five shafts to the Chiltern Tunnel. Tunnel lining segments and viaduct sections are manufactured on site. The compound provides overnight accommodation for staff working on the TBMs.

Chiltern Tunnel South Portal looking north towards the M25 – Jul. 2018 (02_57)
South tunnel portal looking north from the A412 towards the M25 – Nov. 2021 (02_179)
Looking north towards the south tunnel portal from Park Lane Harefield – June. 2022 (02_201)
Looking south across the route as it leaves the Colne Valley viaduct – Apr. 2022 (02_200)
Looking south towards South Tunnel portal across the M25 – Apr. 2022 (02_199)
South Tunnel portal compound looking west – Apr. 2022 (02_198)
Tilehouse Lane cutting and overbridge looking west – Apr. 2022 (02_197)
Looking south along the route towards Tilehouse Lane overbridge – Apr. 2022 (02_196)
Looking south towards the West Hyde embankment and the Colne Valley viaduct – Nov. 2021 (02_195)
South tunnel portal looking north west – Nov. 2021 (02_194)
Treated slurry removed for landscaping – Mar. 2022 (02_193)
Slurry treatment plant – Mar. 2022 (02_192)
Looking north along the route towards the tunnel portal – Mar. 2022 (02_191)
Looking south towards Tilehouse Lane overbridge – Mar. 2022 (02_190)
Viaduct precast factory – Mar. 2022 (02_189)
Viaduct segment framework – Mar. 2022 (02_188)
Viaduct segments – Mar. 2022 (02_187)
Tunnel lining segments – Mar. 2022 (02_186)
Tunnel lining segments curing for 28 days – Mar. 2022 (02_185)
Material re-cycling plant – Mar. 2022 (02_184)
Looking south towards Tilehouse Lane and the North Orbital Road – Mar. 2022 (02_183)
Concrete batching plant – Mar. 2022 (02_182)
Chiltern Tunnel main compound – Apr. 2021 (02_176)
Tunnel precast factory – Oct. 2021 (02_175)
Tunnel precast factory – Oct. 2021 (02_174)
Each segment weighs 8 tonnes – Oct. 2021 (02_173)
Slurry treatment plant and filter press – Oct. 2021 (02_171)
Slurry treatment plant – Oct. 2021 (02_169)
Slurry treatment plant – Oct. 2021 (02_168)
Slurry filter press (the largest in the world) – Oct. 2021 (02_167)
Slurry filter press – 13 tonnes are processed every 25 mins – Oct. 2021 (02_166)
South tunnel portal looking north – Oct. 2021 (02_165)
Tunnel transporter – Oct. 2021 (02_164)
Looking south along the route from the tunnel portal – Oct. 2021 (02_163)
Tilehouse Lane looking north towards overbridge construction – Oct. 2021 (02_159)
Tilehouse Lane looking north towards overbridge construction – Oct. 2021 (02_158)
South tunnel portal looking south across the Tilehouse Lane overbridge – Jul. 2021 (02_152)
South tunnel portal looking west – Jul. 2021 (02_150)
South tunnel portal looking west showing TBM ‘Cecilia’ shortly after launch – Jul. 2021 (02_148)
TBMs ‘Cecilia’ & ‘Florence’ – May 2021 (02_147)
TBM named ‘Cecilia’ under construction – May 2021 (02_146)
Beginning of tunnel showing first lining section – May 2021 (02_144)
Looking forward towards the cutting shield – May 2021 (02_143)
Tunnel lining segment lifted into place – May 2021 (02_142)
South Tunnel Portal looking south -Jun. 2020 RA (02_135)
Tilehouse Lane overbridge looking north – Apr. 2021 (02_133)
Tilehouse Lane closed for the construction of the overbridge – Mar. 2021 (02_125)
Looking north towards the tunnel portal from Tilehouse Lane – Mar. 2021 (02_124)
Tilehouse Lane looking north – Jan. 2021 (02_120)
Looking south from Tilehouse Lane towards the A412 – Jan. 2021 (02_118)
Colne Valley viaduct haul road south from Tilehouse Lane ) Dec. 2020 (02_114)
Viaduct haul road looking east from Tilehouse Lane – Dec. 2020 (02_113)
Chiltern Tunnel South Portal – Dec. 2020 (02_112)
West Hyde embankment looking north – Oct. 2020 (02_109)
Chiltern Tunnel south portal looking north – Oct. 2020 (02_107)
Chiltern Tunnel south portal looking south – Oct. 2020 (02_105)
Chiltern Tunnel south portal looking east – Oct. 2020 (02_104)
Tilehouse Lane looking north towards a concrete batching plant – Aug. 2020 (02_100)
Tilehouse Lane looking north – Aug. 2020 (02_98)
South Tunnel Portal looking north – Aug. 2020 (02_94)
Tilehouse Lane looking south towards the viaduct – Aug. 2020 (02_90)
Tilehouse Lane looking north – Aug. 2020 (02_88)
Tilehouse Lane looking north – Aug. 2020 (02_86)
South Tunnel Portal – Aug. 2020 (02_83)
South tunnel portal looking west – Jul. 2020 (02_79)
South tunnel portal looking north – Jul. 2020 (02_78)
South tunnel portal looking north – Jul. 2020 (02_77)
Tilehouse Lane looking north – Jul. 2020 (02_76)
Tilehouse Lane looking north – Jul. 2020 (02_75)
Tilehouse Lane looking north – Jul. 2020 (02_72)
South Tunnel Portal – Oct. 2019 (02_69)
South Tunnel Portal – Oct. 2019 (02_68)
Chiltern Tunnel Construction Compound – Oct. 2019 (02_67)
Chiltern Tunnel Construction Compund looking south – Oct. 2019 (02_66)
Tunnel South Portal looking north – May 2020 (02_64)
Colne Valley Viaduct and Cutting – Apr. 2016 (02_62)
Cutting looking north – Apr. 2016 (02_61)
Cutting looking north – Mar. 2019 (02_59)
Chiltern Tunnel South Portal Compound looking north – Jul. 2018 (02_56)
Chiltern Tunnel South Portal Compound looking north – Jul. 2018 (02_55)
South Tunnel Portal Construction Compound – Mar. 2019 (02_54)
Chiltern Tunnel South Portal – Mar. 2019 (02_53)
Maple Cross looking north – Jul. 2018 (02_52)
Tilehouse Lane looking south – Aug. 2010 (02_51)
Tilehouse Lane looking south – Jun. 2018 (02_50)
Tilehouse Lane looking south Jun. 2019 (02_49)
Tilehouse Lane – May 2020 (02_48)
Tilehouse Lane – May 2020 (02_47)
Tilehouse Lane – Jun. 2019 (02_46)
Tilehouse Lane looking south – Jun. 2019 (02_45)
Tilehouse Lane looking west – Jun. 2019 (02_44)
Tilehouse Lane looking west – Jun. 2019 (02_43)
Tilehouse Lane looking west – May 2020 (02_42)
Tilehouse Lane looking east – May 2020 (02_41)
Tilehouse Lane looking east – May 2020 (02_40)
Tilehouse Lane looking east – May 2020 (02_39)
Tilehouse Lane looking looking north – Jun. 2019 (02_35)
Tilehouse Lane looking north – May 2020 (02_34)
Tilehouse Lane looking north – Jun. 2019 (02_33)
Tilehouse Lane looking north – May 2020 (02_32)
Tilehouse Lane looking north – May 2020 (02_31)
Tilehouse Lane looking north – May 2020 (02_30)
Tilehouse Lane looking north – May 2020 (02_28)
PRoW RK4 looking north – Aug. 2010 (02_27)
PRoW RK4 looking south – Aug. 2010 (02_26)
PRoW RK4 looking north – Aug. 2018 (02_25)
PRoW RK4 looking north – Aug. 2018 (02_24)
PRoW-RK4 looking north – Jun. 2019 (02_22)
PRoW RK4 south – Jun. 2019 (02_20)
PRoW RK4 looking north – Jun. 2019 (02_21)
PRoW RK4 – May 2020 (02_19)
PRoW RK4 looking north – May 2020 (02_18)
PRoW RK4 looking north – May 2020 (02_17)
Chalfont Lane looking north – Jun. 2018 (02_16)
Chalfont Lane looking south – Sep. 2017 (02_15)
Chalfont Lane looking south – Oct. 2019 (02_14)
PRoWs CP44 and RK2, Chalfont Lane – Aug. 2020 (02_13)
Tunnel Portal looking south – Jul. 2017 (02_12)
M25 slip roads – Jul. 2018 (02_11)
M25 looking west – Aug. 2010 (02_10)
Chalfont Lane looking east – Sep. 2017 (02_09)
M25 slip road looking east – Sep. 2017 (02_08)
M25 slip road looking west – Jul. 2019 (02_07)
Clockwise M25 slip road – Oct. 2019 (02_06)
Link road and M25 slip roads – Sep. 2017 (02_04)
Temp. link road looking west – Jun. 2018 (02_03)
Temp. Link Road – Jun. 2019 (02_02)
Temp. Link Road – Jun. 2019 (02_01)