Hounslow mainline to Heathrow line

[A S Leib]

Given possible expansions of Heathrow Airport, how feasible would a line from Hounslow (mainline, not Tube) be? I started writing this and came up with more problems the longer I thought about it. Dealing with the problems first, in no particular order:

• New third-rail electrification
• Slow compared to Paddington
• Lack of Waterloo / SWML capacity
• Other priorities for Heathrow, London...
• Lack of platform capacity at Heathrow
• Relatively low SWR stock density
• Less money from trains for the airport

(Expanded versions: )

• I don't know whether the ORR would be happy with new third rail electrification. Going off of the Northern line Battersea extension, underground cases might face less resistance.
• Hounslow to Waterloo is currently ~38 minutes (so likely 45+ minutes from Heathrow). Even factoring in taking longer to change for unfamiliar tourists and with more luggage, Heathrow to Waterloo (or Victoria) is unlikely to take more than an hour via Paddington, or even via Earl's Court.
• I don't know how much capacity there is beyond Hounslow having two fewer tph to Waterloo via Brentford than pre-Covid. 2 tph doesn't seem enough to justify a line of this likely cost, there might not be anywhere else for them to terminate, and anywhere short of Clapham Junction seems like a waste as well.
• Having a third rail link from Heathrow to central London doesn't seem likely to go down well if it's instead of rather than as well as a long list of other projects: Heathrow to Slough or Staines, Crossrail 2 (which would also likely mean more services could run on a Hounslow to Heathrow connection if built), southeast Bakerloo line, rail links to Bristol, Leeds or Glasgow Airport...
• 4 tph at Terminal 4 and 6 tph at Terminal 5 mainline stations, all terminating, doesn't leave tonnes of capacity with current platforms. I know that 4+ tph using the same platform's theoretically possible (e.g. on the Watford DC/Lioness line) but it isn't particularly desirable, especially with the risk of importing delays. As fun as it is to imagine Piccadilly line trains running into Waterloo, I'd be surprised if there's enough capacity or timetable resilience to use the Underground platforms either, especially assuming TfL would prefer to see more frequent Acton services.
• I'm fairly sure that all current SWR stock has fewer seats than 345s or 1972 or 2024 Stock (but not necessarily fewer than Electrostars), so wouldn't make a massive difference in terms of total capacity.
• Heathrow might not see more non-Heathrow Express options (or Hayes & Harlington line; do they get money from Elizabeth Line services?) as a net benefit financially, though I'm sure they'd prefer having a third runway approved and no Heathrow Express at all to two runways and fewer rail competitors.

After that fairly long list of problems, onto the advantages.

• 6 tph (being optimistic) would take Heathrow services up from 22 tph to 28 tph, which is still a sizeable increase.
• Between Waterloo / Waterloo East and Clapham Junction, most of south London and Kent to Dorset could get to Heathrow with one change; useful if Gatwick doesn't have cheap or convenient flights or is more expensive.
• Hounslow and stations towards Waterloo would have a more frequent service (assuming skipping stations neither saves time nor is desirable due to Heathrow Express competition). This is very much using a sledgehammer to crack a nut.

 

[JonathanH]

Don't forget in trying to put more trains between Brentford and Hounslow that the capacity is earmarked for the possible 'West London Orbital' service to Hendon.

I don't see a space in the streetscape for a junction off the Hounslow Loop towards Heathrow. Where are you thinking a tunnel portal would be placed?

 

[A S Leib]

Where are you thinking a tunnel portal would be placed?

I wasn't thinking about that and came up with half a dozen problems, plus the ones you've mentioned, before I could think about that aspect any more.

 

[Failed Unit]

I think all the times it was looked at in the past level crossings where also highlighted as an issue. They would be down for an unacceptable amount of time for the motor-vehiles

I think some of the early proposals of getting a direct train will Reading will have gone because of the opening of Old Oak common station.

The arguments of getting into the SouthWest region are still strong in my option. It will never compete on time with the Elizabeth line. However getting passengers to Clapham Junction will be very positive. Just in the same way someone travelling from Bracknell - Gatwick Airport would change there. East Croydon - Heathrow? I suspect will really depend on time / comfort to if someone would choose to change at Clapham Junction or Farringdon.

I don’t think Heathrow Express is competition anyway. The time you spend on the tube getting to somewhere such as Waterloo, I think you will probably have a better journey on any kind of service taking you towards Waterloo directly, even if it did stop at every blade of grass.

 

[Armchair Bob]

Extend the Brentford branch from Southall the short distance into the Hounslow Loop line (on a viaduct - about a quarter of a mile), which has been mooted in the past, and a service can run to Clapham Junction. This would go some way to solve the problem.

 

[A S Leib]

Extend the Brentford branch from Southall the short distance into the Hounslow Loop line (on a viaduct - about a quarter of a mile), which has been mooted in the past, and a service can run to Clapham Junction. This would go some way to solve the problem.

It solves some of the issues with my original suggestion, whilst keeping others (e.g. Heathrow platform capacity), and I don't know what the best rolling stock would be (700s already have experience with airport services, but I don't know if there's any which could be spared or could be built as a relatively small order).

 

[SynthD]

Why specifically from Hounslow, rather than Feltham? It’s twice the distance, with no viable worksite, no fast trains from Waterloo. Add on some works to close level crossings. After that, how was the play it seems doable. Is there demand for it? Hounslow is near the tube station with good service. Feltham and Kingston have direct and relatively speedy buses, Richmond and Twickenham do not.

 

[A S Leib]

Why specifically from Hounslow, rather than Feltham? It’s twice the distance, with no viable worksite, no fast trains from Waterloo.

That's another case of me simply not having thought it through. I don't know off-hand if Richmond's still missing services compared to pre-Covid, which Hounslow is, though whichever capacity issues there are would be the same by Barnes either way.

 

[Farnborough]

Any new provision from Heathrow needs to be towards the south-west - to Woking and beyond (Basingstoke and Guildford)

More London-bound is just a waste of a scarce resource.

 

[Tramtrain]

Any new provision from Heathrow needs to be towards the south-west - to Woking and beyond (Basingstoke and Guildford)

More London-bound is just a waste of a scarce resource.

A connection from T5 to Virginia Water would open up the possibility of Paddington/Old Oak Common/Heathrow (possibly using the Heathrow Express paths) to Basingstoke/Guildford/Woking and Bracknell/Wokingham/Reading (and possibly to places like Oxford beyond Reading). That would be a pretty hefty improvement in connectivity for Berkshire/Surrey and further south/southwest.

 

[Farnborough]

A connection from T5 to Virginia Water would open up the possibility of Paddington/Old Oak Common/Heathrow (possibly using the Heathrow Express paths) to Basingstoke/Guildford/Woking and Bracknell/Wokingham/Reading (and possibly to places like Oxford beyond Reading). That would be a pretty hefty improvement in connectivity for Berkshire/Surrey and further south/southwest.

I'll settle for T5 platforms 1 and 2 to Woking, and onto Guildford and Basingstoke - this offers interchange opportunities to further afield.

As I've said a number of times on these fora, I don't think through trains to Paddington are a good idea... it just adds potential for FUBAR on the time-critical sections.

 

[Recessio]

There was an Ian Visits article on this earlier this week, but to Staines rather than Hounslow: https://www.ianvisits.co.uk/article...or-elizabeth-line-extension-to-staines-92275/

An extension of the Elizabeth line to Staines-upon-Thames could be back on the cards after a call for expanding Heathrow Airport to come with improved public transport links.

In its response to the Department for Transport’s (DfT) consultation on proposed amendments to the draft Heathrow Expansion National Policy Statement (HENPS), the London Assembly Transport Committee wrote a letter to the Rt Hon Heidi Alexander MP, Secretary of State for Transport, outlining its concerns about how transport will cope with additional passenger numbers.

Because the proposed third runway won’t require a new terminal building, the airport has previously argued that substantial public transport upgrades wouldn’t be required.

However, the London Assembly notes that roughly half of airport passengers currently arrive by road, and increased passenger numbers would increase road congestion unless work is done to move more people onto public transport.

However, the letter says that the Committee is concerned about increased crowding and reduced reliability on the Piccadilly line and the creation of substantial new demand on the Elizabeth line.

The letter does not mention the oft-rumoured debate over whether the Heathrow Express will be renewed when its track access agreement with Network Rail expires in 2028. However, TfL has previously raised the issue, asking if the express service is the best use of the railway capacity.

The Heathrow Express is a premium service that uses trains better suited to lots of luggage and offers a faster connection to central London. However, it carries, on average, around 80 passengers per train, compared to its potential capacity of 374.

If the Elizabeth line took over the four slots currently used by the Heathrow Express, the larger Elizabeth line trains could increase capacity by around 5,600 passengers per hour.

What the London Assembly does focus on though is the lack of public transport links to the west of Heathrow Airport.

Two options are being proposed.

There’s a currently on hold Western Rail Link, which would make it easier for rail passengers coming in via Reading to go directly to the airport without needing to change at Hayes or Paddington and come back out again. The report says that the “business case for the Western Rail Link is ‘positive’ but that funding needs to be made available for Network Rail to develop a more detailed design”

The committee also expressed concerns about the lack of southern rail access to Heathrow. A private group is promoting the Southern Rail Link, but TfL has also looked at extending the Elizabeth line to Staines.

Staines has previously been suggested as an ideal terminus for an extended Elizabeth line, as there’s space to expand the station and add the extra platforms needed, and the station is next to a junction that feeds passengers towards Bracknell or Windsor in the west and Waterloo in central London.

A Staines extension would almost certainly require releasing the paths currently used by the Heathrow Express for the Elizabeth line, and another order for more trains to handle the extra mileage. And a new depot for the trains.

A point to note is that letters of this sort are the opening salvo in a negotiating stance. TfL isn’t going to want to miss out on the chance of extending the Elizabeth line if it can get Heathrow Airport to pick up a large chunk of the cost as a condition of building its new runway.

Whether it gets it is another issue, but a combination of the Western Rail Link (if shared with the Elizabeth line) and an Elizabeth line Staines-upon-Thames extension could make the tube map look rather interesting.

 

[NCT]

There’s something called the Southern Rail Link to Heathrow. There are plenty of challenges, but it’s a formal proposal.

 

[Bald Rick]

There’s something called the Southern Rail Link to Heathrow. There are plenty of challenges, but it’s a formal proposal.

That depends on the definition of the word ‘formal’. AIUI it’s not in any plans for funding from Government or Heathrow.

 

[Mr. SW]

As a former local, I've been reading the above and wondering if something could be made of it. So I came up with this.
Map 1: Hounslow Loop in Red, Piccadilly in Light Blue, my line in gold.
The new line would leave the Hounslow Loop at Oaklands Junction which is is situated at Bridge Road and descend sharply (1 in 50/2% gradient -ish) into a tunnel under Inwood Park before calling at Hounslow Treaty Station south of the Treaty Centre before looping round to serve Hounslow West (Picc interchange).
Note that the line leaves the Loop before Hounslow station as this is demanded by the location of open areas for worksites etc. As it is a tiny portion of the council depot, an allotment and a small portion of Inwood Park is taken. There will be no significant demolition. The line curves between Treaty and West stations as there are large buildings here which will have deep piled foundations, not helped by the underlying geology of clay and gravel.

Map 2: Now the line follows one of the original proposed alignments of the Picc Heathrow Extension and calls at Cranford Berkeley Arms (A courtesy station. It would not be strictly necessary but keeping the locals on-side means that it may have to be constructed anyway even though I suspect the usage to be low). The line runs under the Picc between West station and Henley's Corner. Bath Road Harlington Station is at actually quite an important Road Junction where a number of bus routes intersect.

Map 3: Here the line finishes and connects with the existing. Black is the Elizabeth Line and Heathrow Express.

Well, that was an interesting thought experiment and here is my verdict on the exercise.

It's an utter heap of do-do.

It's simply a cross between the Piccadilly and Elizabeth Lines, but worse in every way. It's extractive, expensive, does not serve Twickenham, Richmond or Staines. It over-traffics the Hounslow Loop, with knock-on effects all the way into London. It tried for a moment to see if it could be incorporated into the West London Orbital scheme but I found that way madness lies. I fiddled with another more direct route that followed Staines Road, but that was even worse, serving next to nothing.

But what it has proved is that the routes to Staines and/or to Langley/Slough are the only viable schemes, and these are the ones that should be promoted.

 

[Class15]

As a former local, I've been reading the above and wondering if something could be made of it. So I came up with this.
View attachment 211072Map 1: Hounslow Loop in Red, Piccadilly in Light Blue, my line in gold.
The new line would leave the Hounslow Loop at Oaklands Junction which is is situated at Bridge Road and descend sharply (1 in 50/2% gradient -ish) into a tunnel under Inwood Park before calling at Hounslow Treaty Station south of the Treaty Centre before looping round to serve Hounslow West (Picc interchange).
Note that the line leaves the Loop before Hounslow station as this is demanded by the location of open areas for worksites etc. As it is a tiny portion of the council depot, an allotment and a small portion of Inwood Park is taken. There will be no significant demolition. The line curves between Treaty and West stations as there are large buildings here which will have deep piled foundations, not helped by the underlying geology of clay and gravel.
View attachment 211081
Map 2: Now the line follows one of the original proposed alignments of the Picc Heathrow Extension and calls at Cranford Berkeley Arms (A courtesy station. It would not be strictly necessary but keeping the locals on-side means that it may have to be constructed anyway even though I suspect the usage to be low). The line runs under the Picc between West station and Henley's Corner. Bath Road Harlington Station is at actually quite an important Road Junction where a number of bus routes intersect.
View attachment 211082
Map 3: Here the line finishes and connects with the existing. Black is the Elizabeth Line and Heathrow Express.

Well, that was an interesting thought experiment and here is my verdict on the exercise.

It's an utter heap of do-do.

It's simply a cross between the Piccadilly and Elizabeth Lines, but worse in every way. It's extractive, expensive, does not serve Twickenham, Richmond or Staines. It over-traffics the Hounslow Loop, with knock-on effects all the way into London. It tried for a moment to see if it could be incorporated into the West London Orbital scheme but I found that way madness lies. I fiddled with another more direct route that followed Staines Road, but that was even worse, serving next to nothing.

But what it has proved is that the routes to Staines and/or to Langley/Slough are the only viable schemes, and these are the ones that should be promoted.

I really love this actually.

 

[MattRat]

Wouldn't it be cheaper to build such a line just after Feltham? There's a park and open land you could build a viaduct over to go to terminal 4. I'm aware of the elevation changes but I think there might be enough room to squeeze it all in as soon as you leave the urban area of Feltham

 

[minimann]

Personally, if southern rail link happens an extension of west London orbital feels the most sensible option. Unfortunately things like the Brentford branch would trash a lot of the great west road to swing it around and doesn't really deliver much on top of Crossrail. I'm still a bit surprised no one is making the case for WLO to Feltham even now as it would really support the housing growth and connectivity of that area which is car dominated

 

[cle]

Personally, if southern rail link happens an extension of west London orbital feels the most sensible option. Unfortunately things like the Brentford branch would trash a lot of the great west road to swing it around and doesn't really deliver much on top of Crossrail. I'm still a bit surprised no one is making the case for WLO to Feltham even now as it would really support the housing growth and connectivity of that area which is car dominated

I agree that Hounslow feels a little premature, it’s not actually a busy station (1m p/a) - and doesn’t even have a handy bay from yesteryear. The turnback is a faff at metro frequency.

I always thought swinging around to Twickenham might be more appealing for various reasons. But heading to Heathrow, even if the long way via Staines, would I’m sure be very well used. But would enable Waterloo via CJ/Richmond also - as that might only be 2tph which isn’t viable frequency for big civils…

 

[Tramtrain]

As I've said a number of times on these fora, I don't think through trains to Paddington are a good idea... it just adds potential for FUBAR on the time-critical sections.

What is time critical? The Woking line through Chertsey is quiet, as is the Reading/Wokingham/Ascot line. If you use the existing Heathrow Express paths, which are very rarely delayed, there aren't really any critical points. If it's the Paddington WCML part that is the worry, trains could be turned back at Heathrow if there are delays on that stretch. The added connectivity you'd get connecting Woking/Basingstoke (and Wokingham/Bracknell/Ascot) to Old Oak Common with one stop is immense. Similarly, one stop onto EL services through central london. It could make the whole business case of a southern railway connection much broader.

 

[Farnborough]

If you use the existing Heathrow Express paths... Similarly, one stop onto EL services

Heathrow is the destination - and the existing HEx paths are in use...

In any case, having 2tph from each of Basingstoke/Guildford via Woking to LHR T5 offers one-change onto the Elizabeth Line (hence OOC) at LHRT5 without taking any existing paths... plus HEx only has four trains per hour, which rules out additional routes such as Ascot-Bracknell-Wokingham, Asoct-Frimley-Aldershot, or Richmond-Twickenham (whatever the merits of those routes may be)