Last update 19 June 2026
Mileages are given in the form miles.chains unless stated otherwise. Figures prefixed with ≈ are approximate, those in parentheses are not on this route but are given for reference. Reference to 'start'/'end' of an asset are as read down the page.
0.00 Northolt Junction with ANL (10.15) and NAJ1 (0.00) 0.07 SOUTH RUISLIP formerly NORTHOLT JUNCTION; S. R. & NORTHOLT JUNCTION (0.50) RUISLIP GARDENS London Underground 0.56 RUISLIP GARDENS 1.68 WEST RUISLIP formerly R. & ICKENHAM 1.78 connection to Ruislip depot London Underground 2.61 Copthall Junction (future provision) 3.27 SOUTH HAREFIELD formerly H. 3.44 Denham East Junction with Denham East Curve (0.00) 3.76 Denham West Junction with DEM (0.00) and start of Denham viaduct 4.05 end of Denham viaduct 4.17 start of Colne viaduct 4.23 end of Colne viaduct 4.50 DENHAM 5.42 DENHAM GOLF CLUB 6.16 start of Chalfonts No 1 viaduct 6.21 end of Chalfonts No 1 viaduct 6.35 start of Chalfonts No 2 viaduct 6.43 end of Chalfonts No 2 viaduct 6.54 start of A413 viaduct 6.62 end of A413 viaduct 7.18 GERRARDS CROSS 9.75 SEER GREEN formerly BEACONSFIELD GOLF LINKS; S. G.; S.G. & JORDANS 11.41 BEACONSFIELD 14.13 Sir Philip Rose's viaduct 15.62 Gomme's siding 15.71 Gordon Road viaduct 16.11 Wycombe South Junction with WBB (33.68) 16.29 HIGH WYCOMBE formerly W. 16.61 Hughenden Road viaduct 17.14 High Wycombe goods depot 18.48 WEST WYCOMBE 21.27 SAUNDERTON 21.76 divergence of up and down lines 24.15 convergence of up and down lines 24.40 PRINCES RISBOROUGH [2] PRINCES RISBOROUGH [1] 24.48 Princes Risborough Junction with PRA (42.31) 24.48 junction with PRC (0.00) and PRT/THA (0.00) 27.16 ILMER 29.74 HADDENHAM 30.25 HADDENHAM & THAME PARKWAY 30.75 River Thame viaduct 33.55 Ashendon Junction with GUA (165.21) up line 33.69 Ashendon Junction with NAJ3 (0.00) Note that Ashendon Junction down line junction is on NAJ3