Chiltern Tunnel North Portal

Trains will emerge from the Chiltern Tunnel into South Heath cutting which will be 16 metres deep. The portal is on farmland just north of Frith Hill. The construction compound will be approximately 1.5ha in size and be in place for eight years. Access to the compound will be via a newly constructed temporary haul road from the Link Road roundabout on the A413 at great Missenden. Realignment of one PRoW (Public Right of Way) will be required. Footpath GMI 13 will be closed during construction and then be permanently diverted to the south of the tunnel portal.
The former Weights & Measures Gym (previously the Black Horse public house) was demolished to allow permanent access to the portal from Frith Hill. A series of 96 piles (barrettes) were installed to the north of Frith Hill to support the last 200 metres of the tunnel through soft clay. There will be an ancillary building and an area of hard standing alongside the track within the South Heath cutting.
The tunnel boring machines reached here in February and March 2024. They were then be dismantled and removed.
North of the tunnel portal The contractors change from Align JV who are building the Colne Valley viaduct and the Chiltern tunnel to EKFB who will construct the railway across Buckinghamshire.
Please note the tunnel portal is the tunnel’s entrance. The tunnels will have porous portals made from concrete and designed to allow the passage of air from the tunnel to reduce both air pressure changes and the noise generated when trains enter and leave the tunnel.

Chiltern Tunnel north portal looking east – May 2016 (08_58)
Chiltern Tunnel north portal looking west – Apr. 2016 (08_57)
Looking north beyond the north tunnel portal – Jun. 2024 (08_160)
Looking east across the north tunnel portal – Jun. 2024 (08_159)
Looking west across the north tunnel portal towards Great Missenden – Jun. 2024 (08_158)
Looking west across the north tunnel portal – Jun. 2024 (08_157)
Construction of the concrete batching plant for tunnel walkways and three overbridges – Jun. 2024 (08_156)
Dismantling the TBMs – May 2024 (08_155)
Chiltern Tunnel north portal – May 2024 (08_154)
Dismantling the TBMs – May 2024 (08_153)
Dismantling the tunnelling shield – May 2024 (08_152)
TBM Cecilia breakthrough at Chiltern Tunnel North Portal – Mar. 2024 (08_151) HS2 picture
TBM Florence in the ‘up’ tunnel – Mar. 2024 (08_150)
TBM Cecilia in the ‘down’ tunnel – Mar. 2024 (08_149)
Looking north towards the South Heath cutting – Mar. 2024 (08_148)
Looking south towards the tunnel portal – Mar. 2024 (08_147)
Cecilia’s cutting head – Mar. 2024 (08_146)
The ‘up’ London bound tunnel portal – Mar. 2024 (08_145)
Florence’s tunnelling shield – Mar. 2024 (08_144)
Florence’s cutting head – Mar. 2024 (08_143)
TBM Florence breakthrough in the ‘up’ London bound tunnel – Feb. 2024 (08_142) HS2 picture
Looking west over the tunnel north portal towards Great Missenden – Jan, 2024 (08_139)
Preparing the north tunnel portal for the TBM’s arrival – Jan. 2024 (08_138)
Looking south along the South Heath cutting towards the tunnel portal – Aug. 2016 (08_96)
Looking north across the north tunnel portal – May 2019 (08_106)
Concrete pouring at the north tunnel portal – Oct. 2023 (08_139)
Concrete pouring at the north tunnel portal – Oct. 2023 (08_138)
Formwork for recess in base for TBM track exiting the ‘up line’ tunnel – Oct. 2023 (08_137)
Looking north towards the South Heath cutting past the north portal ancillary building – Oct. 2023 (08_136)
Down line tunnel portal looking north towards along the porous portal base – Aug. 2023 (08_135)
North tunnel portal headwall – Aug. 2023 (08_134)
Concrete pour for the porous portal base – Aug. 2023 (08_133)
Concrete pour for the porous portal base – Aug. 2023 (08_132)
Concrete pour for the porous portal base – Aug. 2023 (08_131)
Concrete pour for the porous portal base – Aug. 2023 (08_130)
Looking east across the north portal towards Jenkin’s Wood – Jul. 2023 (08_129)
Looking north from the down line portal – Jul. 2023 (08_128)
Looking south towards the up line portal – Jul. 2023 (08_127)
Down line porous portal base slab – Jul. 2023 (08_126)
Looking south towards the tunnel portal – Jul. 2023 (08_125)
Construction of lineside ancillary building – Jul. 2023 (08_124)
Excavating the South Heath cutting – Jul. 2023 (08_123)
Looking north from Frith Hill to the north tunnel portal and South heath cutting – Jun. 2023 (08_122)
North tunnel portal looking east towards Potter Row – Jun. 2023 (08_121)
North tunnel portal looking west towards Great Missenden – Jun. 2023 (08_120)
North tunnel portal and South Heath cutting looking west – Jun. 2023 (08_119)
Looking north towards the South Heath cutting from the portal west flank wall – Jun. 2023 (08_118)
Looking north towards the porous portals and South Heath cutting – Jun. 2023 (08_117)
Looking south along the South Heath cutting towards the Chiltern tunnel north portal – Jun. 2023 (08_116)
Assembling the reinforcing bars for the porous portal bases – Jun. 2023 (08_115)
Looking south towards the Chiltern tunnel north portal headwall – Jun. 2023 (08_114)
Looking south towards Frith Hill – Mar. 2023 (08_113)
Permanent access road to the north portal – Mar. 2023 (08_112)
Looking north towards the South Heath cutting – Mar. 2023 (08_111)
Looking south from the Align compound towards Frith Hill – Feb. 2023 (08_110)
Storage pond for water removed from tunnel portal – Feb. 2023 (08_109)
Constructing the headwall capping beam – Feb. 2022 (08_108)
Looking north from the headwall along the South Heath cutting – Feb. 2023 (08_107)
Permanent north portal access road looking north – Feb. 2023 (08_105)
Permanent north portal access road looking north – Feb. 2023 (08_104)
Permanent north portal access road looking north – Feb. 2023 (08_103)
Permanent tunnel portal access road looking north from PRoW GMI 13 – Feb. 2023 (08_102)
Looking south along the South Heath cutting towards the north tunnel portal – Feb. 2023 (08_101)
The Chiltern Tunnel north portal – Feb. 2023 (08_100)
Looking east towards the tunnel portal – Jan. 2023 (08_98)
Looking north towards the South Heath cutting – Jan. 2023 (08_97)
Looking east along PRoW GMI 13 towards Jenkin’s Wood – May 2019 (08_95)
Looking south towards Frith Hill across the north tunnel portal construction compound – Nov. 2022 (08_94)
Looking north towards South Heath cutting and the PRoW GMI 12 overbridge – Dec. 2022 (08_89)
Construction of the access road to the north portal – Dec. 2022 (08_88)
Looking north across Frith Hill towards the north portal – Oct. 2022 (08_87)
North tunnel portal looking east – Oct. 2022 (08_86)
Looking south from PRoW GMI 12 overbridge towards the tunnel portal – Oct. 2022 (08_85)
North portal construction – Sep. 2022 (08_84)
Excavating the barrettes – Sep. 2022 (08_82)
Excavating the barrettes – Sep. 2022 (08_81)
Excavating the breakout plug – Sep. 2022 (08_80)
Excavator grab – Sep. 2022 (08_79)
Looking east across the tunnel portal and piling for tunnel support barrettes – May 2022 (08_77)
Looking west across the tunnel portal and South Heath cutting towards Great Missenden – May 2022 (08_76)
Looking east towards the tunnel portal and Jenkin’s Wood – May 2022 (08_74)
Diaphragm walling grab – May 2022 (08_73)
Diaphragm walling grab – May 2022 (08_71)
Looking north along the South Heath cutting from the north tunnel portal – May 2022 (08_70)
Looking south across barrette construction towards Frith Hill – May 2022 (08_69)
Looking west towards storage silos and slurry treatment plant – May 2022 (08_68)
Water and bentonite storage silos – May 2022 (08_67)
Slurry treatment plant – May 2022 (08_66)
Water being delivered by tanker from local water supply – May 2022 (08_65)
Looking south east towards Frith Hill – May 2022 (08_64)
Frith Hill looking east – May 2022 (08_63)
Frith Hill looking north – May 2022 (08_62)
North tunnel portal looking north – Apr. 2022 (08_61)
South Heath cutting looking east – Apr. 2022 (08_59)
Looking north from Frith Hill towards the north tunnel portal – Jan. 2022 (08_55)
Looking north from Frith Hill towards the north tunnel portal – Jan. 2022 (08_54)
Looking north from Frith Hill towards the north tunnel portal – Jan. 2022 (08_53)
Looking north from Frith Hill towards the north tunnel portal – Jan. 2022 (08_52)
Looking north from Frith Hill towards the north tunnel portal – Jan. 2022 (08_51)
Looking north from Frith Hill towards the north tunnel portal – Jan. 2022 (08_50)
Looking north across Frith Hill towards the north tunnel portal – Nov. 2021 (08_ 44)
Looking west across the north tunnel portal – Nov. 2021 (08_43)
Looking east across the north tunnel portal – Nov. 2021 (08_42)
Looking east across the North tunnel portal towards South Heath – Nov. 2021 (08_41)
North tunnel portal looking west – Nov. 2021 (08_40)
Demolition of the former Weights & Measures Gym in Frith Hill – Nov. 2021 (08_39)
The former Weights & Measures Gym – Nov. 2021 (08_38)
Looking towards the north tunnel portal from Frith Hill – Nov. 2021 (08_37)
Looking north towards the tunnel portal from PRoW GMI 16a – Nov. 2021 (08_36)
North tunnel portal looking west – Jul. 2021 (08_32)
Looking north towards the north tunnel portal earthworks from Frith Hill (MJ) – Sep. 2021 (08_31)
North tunnel portal looking west towards the haul road and Great Missenden – Jul. 2021 (08_26)
Chiltern Tunnel north portal looking west – Oct. 2020 (08_23)
Looking north towards the north tunnel portal from Frith Hill – Feb. 2021 (08_22)
The Weights & Measures Gym (formerly the Black Horse) on Frith Hill – Sep. 2021 (08_14)
PRoW GMI 13/3 looking east – Aug. 2016 (08_13)
PRoW GMI 13/3 looking east – Jun. 2019 (08_12)
PRoW GMI 13/3 looking northwest – Aug. 2016 (08_11)
PRoW GMI 13/3 looking west – Jun. 2019 (08_10)
Tunnel Portal looking southwest – Aug. 2016 (08_09)
PRoW GMI 13/3 looking south – Jun. 2019 (08_08)
PRoW GMI 13/3 looking south – May 2019 (08_07)
Tunnel Portal looking north – May 2019 (08_06)
Tunnel Portal looking north – May 2019 (08_05)
PRoW GMI 13/3 looking north – Aug. 2016 (08_04)
PRoW GMI 13/3 looking north – Aug. 2016 (08_03)
PRoW GMI 13/3 looking south towards the north tunnel portal (The Weights & Measure Gym can be seen through the trees) – Aug. 2016 (08_01)