Last update 1 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.
11.04 Heathrow Airport Junction with MLN1 11.15 Heathrow Airport Junction with MLN1 later position of down main line junction 11.47 start of Stockley East Flyover viaduct 11.55 end of Stockley East Flyover viaduct and start of Stockley North viaduct 11.60 start of Sams viaduct 11.74 end of Sams viaduct 11.79 end of Stockley North viaduct 12.00 intersection bridge over MLN1 12.25 HEATHROW INTERCHANGE also called H. JUNCTION 12.30 Heathrow tunnel portal end-on junction with HLL1 and ownership boundary (NR/BAA) Note that this was part of the original HLL