Jez, Excellent.
The main London tunnels pop out at Ruislip Golf Course and its then viaduct across the Colne Valley popping into twin bore tunnels (Chiltern tunnel) again just on the east side of the M25. Should be Two Vent shafts in Chalfont area, one adjacent to Chesham Lane and the other at Bottom House Farm Lane. The two near Amersham are at the A413/A404 roundabout and roughly opposite Mop End Lane east of Little Missenden. The Chiltern tunnel bores terminate at Mantle’s Wood to the west of Hyde Heath north west of Amersham. The M25 slips should be the main works access for the viaduct and Chiltern tunnel construction. Vent shafts are typically used for emergency access during construction. I’m not sure how much construction will be undertaken from the north end of the Chiltern tunnel though obviously the next section interfaces there. Incidentally someone had retagged the Chiltern tunnel way (https://www.openstreetmap.org/way/147166450 ) with railway=construction. I’ve reverted back to railway=proposed until full construction actually starts next year. I know that area quite well too. Back in the 80’s I worked on relocating a pipeline running alongside the A413 Amersham Road by Gerrards Cross to enable the M25 bridge to be constructed there. It was great view of Chiltern Main Line Chalfont Viaduct which never looked like it could accommodate the M25 beneath its arches but does! Cheers Andy From: Jez Nicholson [mailto:[email protected]] Sent: 21 January 2019 14:35 To: Andy Robinson Cc: Talk-GB Subject: Re: [Talk-GB] High Speed 2 route mapping Thank you Andy(s), ...and thanks for the wiki page updates. I'm originally from Chalfont St Peter and my Mum still lives there, so I will be keeping my eye on progress....brings back childhood memories of watching the M25 being constructed in the same place. :) I know that a site in Amersham has been busy with trucks. Regards, Jez On Mon, 21 Jan 2019 at 13:09 Andy Robinson <[email protected]> wrote: Jez, The proposed routes are in OSM. There is a relation for each phase of HS2. See: Phase 1: https://www.openstreetmap.org/relation/1986960 Phase 2a: https://www.openstreetmap.org/relation/6748946 Phase 2b western leg: https://www.openstreetmap.org/relation/6775224 Phase 2b eastern leg: https://www.openstreetmap.org/relation/6775258 Note that 2b eastern leg does not reflect the latest proposed alignment as I’ve yet to see a shapefile for that. I don’t expect any significant changes to proposed 2b western leg. These relations are based upon the alignments (shapefiles) as published by Gov/HS2 and predate hybrid Bill, therefore we can expect tweaks and modifications to the details once main construction commences. I recently added Vesting Declaration interests for all Phase 1 areas to that relation except I think I still need to do Camden which is mostly the Euston block which is mainly under demolition anyway. Some construction areas are mapped by me or by locals and I’m familiar with most of the construction related requirements of phase 1. Note that some current construction work areas for phase 1 are only for enabling works (utility diversions etc.) so expect construction areas to change over 2019 and into 2020. Main contractors who will build phase 1 are not now expected to commence main site works until the first quarter of 2020. It would be good if locals in the greater London area can keep an eye and update construction areas, especially at Euston and at the tunnel vent shaft locations out to Ruislip. The new HS2 sliproads off the M25 at Chalfont could do with a clean up to their proper alignments when some form of access or aerial imagery is available. Cheers Andy (blackadder) From: Jez Nicholson [mailto:[email protected]] Sent: 21 January 2019 11:58 To: Talk-GB Subject: [Talk-GB] High Speed 2 route mapping I'm doing some professional work with High Speed 2 data. Can anyone update or add detail to https://wiki.openstreetmap.org/wiki/United_Kingdom_Railways/High_speed_2 ? I know that @blackadder worked on this. I've also been looking at http://www.thehs2.com/ I also know that there are now some active (pre?) construction sites on the route which could be mapped. ....and, is there any advice or links to discussion on the addition of proposed railway lines? - Jez
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