The Anonymous Widower

HS4Air Between Heathrow And Gatwick Airports

In terms of the number of trains, the route between Heathrow and Gatwick Airports could be one of the businest section of HS4Air.

This map clipped from the Expedition Engineering web site, shows the route of HS4Air between the two airports.

Note that in addition to the tunnels under the two airports, there is another tunnel through sensitive parts of Surrey.

Heathrow Southern Railway And The Southern Portal Of HS4Air’s Heathrow Tunnel

This Google Map shows the first section of the route South from Heathrow.

The two motorways are.

  • The M25 goes roughly North-South.
  • The M3 goes roughly East-West

I said in HS4Air’s Connections To HS2, The Great Western Main Line And Heathrow, that it appears that HS4Air’s Heathrow Tunnel will emerge somewhere just South of where the motorways meet.

The station in the South-East corner is Addlestone on the Chertsey Branch Line.

Follow the line Northward and Chertsey station is visible.

Heathrow Southern Railway intend to use this branch as part of their proposal to create access from the South into Heathrow.

From Chertsey, their route would follow to the East of the M25 and then use a short East-West tunnel to connect into Heathrow Terminal 5.

This Google Map shows the Chertsey Branch Line, where it crosses the M25.

The Chertsey Branch Line goes diagonally across the map from Chertsey station in the South-East corner to the North-West corner.

A Junction just before the Chertsey Branch crosses the M25 would connect to the new railway running on the East side of the M25, towards Heathrow.

So that HS4Air and the Heathrow Southern Railway avoid each other, it would appear that the Southern portal of HS4Air’s Heathrow Tunnel must be to the South of the Chertsey Branch.

Onward To Junction 11 Of The M25

If HS4Air, then followed the M25, it could probably be squeezed in as far as a short distance past Junction 11.

This Google Map shows the section of the M25 around junction 11.

Junction 11 to 12 Of The M25

The first map, shows HS4Air following the M25 and passing over the M25/A3 junction.

This Google Map shows the area around the M25/A3 junction.

The junction between the M25 and the A3 is clearly visible.

On either side of the A3, as it goes South of the junction are the RHS Garden Wisley and Wisley Airfield.

I doubt that HS4Air will go anywhere near the Garden, but the airfield might well be the place, where the tunnel under the North Downs has its Northern portal.

The problem is how does HS4Air get between Junctions 11 for the A320 and Junction 10 for the A3 along the M25.

This Google Map shows the section of the M25.

Junction 11 is in the top-left of the map and Junction 10 is in the bottom right.

  • I have flown my helicopter along the route and in places there is not much space on either side of the road.
  • The road runs through housing in places.
  • The road is very busy.
  • The distance between the junctions 10 and 11 is 3.6 miles.

This page on the Highways England web site, says that the road is to be converted into a four lanes each way smart motorway.

Expedition Engineering obviously have a plan to get the motorway and a double-track high speed railway through this difficult section.

The Surrey Tunnel

I said earlier that the Northern Portal of the |Surrey Tunnel will be on or in the vicinity of Wuisley Airfield.

Putting maps together and taking an educated guess, I wonder if the Southern portal is on this map, which shows an area South of Dorking.

Note the Ibstock brick works. Could this be the site?

This Google Map shows its relationship to Gatwick Airport.

The distance is about nine miles, from the brick works in the top left of the map to the Airport.

According to the first map in this post, the route is mainly on the surface


The route is challenging, but I’m pretty sure, that it can be created.



July 26, 2018 Posted by | Transport | , , | 1 Comment

How Would HS4Air Affect The Western Rail Approach to Heathrow?

The Western Rail Approach to Heathrow (WRAtH), is a proposed new rail route to Heathrow from Reading and Slough.

It has a similar objective to HS4Air’s connection to the Great Western Main Line at Iver.

Both railways would connect Reading and Slough to stations in the Airport.

But in my view the HS4Air approach has several advantages.

  • HS4Air connects to both Heathrow and Gatwick airports and Ashford, whereas WRAtH only connects to Heathrow.
  • It would connect high speed trains from Bristol, Cardiff, Oxford, South Wales and the West of England to Heathrow, Gatwick and Ashford for Continental services.
  • As an example a direct Cardiff-Ashford service would take three hours twenty minutes.
  • Trains would be faster, with an operating speed between Reading and Heathrow of at least 140 mph.

But perhaps most importantly, HS4Air could be a totally privately-funded project.


I feel Network Rail’s proposal for a Western Rail Approach to Heathrow is not needed, if HS4Air is built.


July 26, 2018 Posted by | Transport | , , , , | Leave a comment

How Will HS4Air Affect Heathrow Southern Railway?

Heathrow Southern Railway will be an East-West railway through Heathrow using the existing tunnels, which will connect Basingstoke and Woking to Pasddington via Heathrow and Old Oak Common.

On the other hand HS4Air will be a North-South railway through Heathrow probably in a deep tunnel.

I suspect that numerous escalators, lifts and travelators will be the only connections between the two railways and the various terminals in the airport.


I can see no reason, why both railways can’t be built separately.

Co-operation could be useful to both railways.

If the two railways have a well-designed interchange under Heathrow, this would open up journey possibilities like Southampton-Paris with a change at the airport.

HS4Air is more than just a railway connecting airports and the North of England to the Channel Tunnel.

July 26, 2018 Posted by | Transport | , , , | Leave a comment

HS4Air And Heathrow Airport’s Third Runway

HS4Air will pass under Heathrow Airport in a tunnel, where there will be a new station.

Look at how Crossrail hasn’t resulted in major demolition in Central London.

For this and other reasons, I believe that HS4Air can be built underneath the Airport without affecting what Heathrow do on the surface.

The only effect that a possible third runway and an extra terminal at Heathrow, would be minor changes to the route of the tunnel and the layout of the station.

But I suspect that HS4Air will be built, so that it is totally future-proofed for all possible developments at Heathrow.

On the other hand, HS4Air might have effects on Heathrow Airport.

  • Passengers from the North of England would be more likely to come by high speed train from Birmingham and Manchester.
  • Passengers from South Wales and the West of England would be more likely to come by high speed train from Bristol and Cardiff.
  • The transfer between Heathrow and Gatwick would be less than twenty minutes. HS4Air claim just fifteen.
  • If there was sufficient demand there could be a Heathrow-Gatwick shuttle every 10-15 minutes.

Just as some of these effects will be positive for Heathrow, they will also be positive for Gatwick.


I am led to the conclusion, that some politicians, who are seriously against a third runway at Heathrow, could manage to get the runway blocked or delayed for a decade, by citing HS4Air and Gatwick as a viable alternative.

But that won’t matter, as Gatwick will build the much-needed runway for the South-East and it will be less than twenty minutes from Heathrow.

July 26, 2018 Posted by | Transport | , , , | Leave a comment

HS4Air’s Connections To HS2, The Great Western Main Line And Heathrow

This map clipped from the Expedition Engineering web site, shows the route of HS4Air to the West of London.

Note the M25 running North-South through the area.

The HS4Air And HS2 Junction

This Google Map shows the area, where HS4Air will join HS2.


  1. The M25 running North-South.
  2. The Chiltern Main Line running East-West.
  3. The two stations shown are Denham Golf Club and Denham.
  4. At the top of the map, just to the East of the M25 is a large quarry, which shows up in a beige colour.

The route of HS2 as it passes through the area from North-West to South-East is as follows.

  • HS2 crosses the M25 in a tunnel, at the point where the lane crosses just below the M25 label, at the top of the map.
  • HS2 then goes South East towards Denham on a mixture of cuttings, embankments and viaducts.
  • HS2 then follows the Chiltern Main Line in a cutting towards London.
  • HS2 goes into a tunnel just to the West of West Ruislip station.

It looks to me, that HS4Air will branch off HS2, just to the East of the M25, in the area of the quarry, which is shown in this Google Map.

HS4Air would continue along the M25 motorway towards the South, whilst HS2 will continue in to the South East.

The HS4Air And Great Western Main Line Junction

This Google Map shows the area, where HS4Air crosses the Great Western Main Line.


  1. The M25 running North-South
  2. The M4 running East-West
  3. The Great Western Main Line running East-West.
  4. The two stations are Langley and Iver.
  5. Iver North Water Treatment Works sitting to the North East of where the M25 and the Great Western Railway cross.

This Google Map shows the area, where the M25 and the Great Western Main Line cross in more detail.


  • HS4Air would be following the M25 North-South.
  • Two links to allow trains to go both ways from the Great Western to the Southbound HS4Air, would be needed.
  • These links could loop over the Water Treatment Works.
  • As the M25 will probably need widening, combining both projects would probably benefit both.

I think we could see a spectacular junction.

HS4Air North Of Heathrow

|As the first map shows HS4Air goes underneath Heathrow Airport in a tunnel, where there will be a station in the tunnel.

This map shows the M25 to the North of the Airport.

Terminal 5 at Heathrow is picked out with a station symbol.

I suspect that HS4Air will cross the massive M25/M4 junction on a viaduct and then descend into a tunnel for the Airport.

Or if the third runway at Heathrow is built, the railway could go into tunnel to the North of the motorway junction.

I suspect, the rail tunnels will be very deep under the airport, which will mean the following.

  1. They won’t disturb the existing airport.
  2. All the existing Crossrail design and construction expertise will be useful.
  3. The station could be as large as needed, with through and terminal platforms.

With its connections to Crossrail, it would also be West London’s high speed railway station.

HS4Air South Of Heathrow

South of Heathrow, the first map, shows that the Heathrow tunnel will emerge close to the M25, South of the major junction between the M25 and the M3.

This Google Map shows the area.

I will investigate where the Heathrow Tunnel emerges in HS4Air Between Heathrow And Gatwick Airports.


This section of HS4Air looks to be a railway that can be slotted through alongside the M25 with very little disturbance to existing traffic routes.

I doubt that few houses or other buildings will need to be demolished.

The two major junctions with HS2 and the Great Western Railway will cause little disruption during construction, as the former will be over a quarry and the second is by a sewage works, which could be moved if necessary.

This first section is so obvious, I am surprised it hasn’t been included with the building of HS2.



July 26, 2018 Posted by | Transport | , , , | 1 Comment