HS2’s Northolt Tunnel under the capital is 50% complete

HS2’s tunnelling team are celebrating completing half of the 8.4-mile twin bored Northolt Tunnel underneath London.

Four tunnel boring machines (TBM) are being used the complete the tunnel that will carry high-speed trains between HS2’s super-hub station at Old Oak Common, west London, and the outskirts of the capital at West Ruislip.

The machines will excavate 16.8 miles of tunnel overall – two bores over the 8.4-mile length – making it the second longest tunnel on the new railway after one recently excavated beneath the Chiltern Hills.

The first machine, named Sushila after a local teacher, was launched eastwards from West Ruislip in October 2022. This was followed one month later by TBM Caroline, named after astronomer Caroline Herschel, which is used to excavate the adjacent tunnel.

Both will complete 5 miles of the route, finishing their journeys at the Green Park Way vent shaft in Greenford – just over half way – where they will be lifted out.

Earlier this year, TBM Emily, which is named after Emily Sophia Taylor, began its journey west from HS2’s Victoria Road Crossover Box site near Old Oak Common towards Greenford. She was joined by the fourth machine, named Anne, after Lady Anne Byron, in May. They will both complete 3.4 miles of the tunnel.

Combined, the four machines have now travelled over 8.4 miles – half of the total distance for the twin-bored tunnel. The completion of each tunnel drive will be staggered as they reach the final destination at Green Park Way, with the first TBM, Sushila, arriving later this year.

Between them, the quartet of machines have excavated nearly 2 million tonnes of earth.

The excavated material is being put to beneficial reuse. Around the West Ruislip portal, it is being used around the Copthall Green Tunnel, to remodel a nearby golf course that has been impacted by HS2’s tunnelling and is being used sustainably to create new green spaces in the Hillingdon area surrounding the new railway.

London Clay removed from the Victoria Road Crossover Box side of the tunnel, is being taken to the London Logistics hub using a spoil conveyor. From there it is taken by rail to beneficial reuse sites across the UK in Rugby, Kent and Cambridgeshire. The logistics hub has now transported over 2 million tonnes of materials to these sites, which are being used to backfill quarries to support housing developments and build wildlife areas for birds.

The Northolt Tunnel is being built by a joint venture formed of the companies Skanska, Costain and STRABAG (SCS). The same JV will also construct the Euston Tunnel eastward from Old Oak Common to the centre of London.
When complete, HS2 will improve connections between London and the West Midlands, with trains running further north on existing lines.

The new high speed railway will create quicker and more reliable journeys, driving economic growth while crucially freeing up space for more local trains on the most congested part of the existing West Coast Main Line.

Follow us on social media:

0:00 Introduction
0:11 Walking around Victoria Road Crossover box
1:34 On TBM Caroline
3:20 Inside Victoria Road Ancillary Shaft
4:58 At Westgate Ventilation Shaft
6:09 Progress at South Ruislip Ventilation Shaft
6:58 Exploring Mandeville Road Ventilation Shaft
8:55 The purpose of the Green Park Way Ventilation Shaft
9:38 Outro

#HS2 #Construction #engineering #tunnel #london

[inbb]

Given that the land for the Phase 2 section of the HS2 has not been sold, this HAS to be completed now.
Change the name of this section to something other than HS2 if one wishes to market it better. THIS NEEDS TO GO TO MANCHESTER AT THE VERY MINIMUM.

[owensmith]

If Labour don't restore protection for the route for Phase 2 the Manchester section I will be very disappointed in them. The money to secure the route has been spent, it costs nothing to protect the route so it can be built eventually when finances allow.

[chish]

These are the works that no one ever sees let alone understands how important they all are. And these are the expensive works needed if you don't want a railway on the surface.
Well done HS2 for highlighting what these people are building.

[LazerBenabba-wo]

Another and expected excellent straightforward explanation of what is a highly technical and difficult project.
The videos are brilliant that even a lay person may grasp the intrcacies of this project.

[frasermitchell]

As said by another contributor, this tunnel was a political decision because of the Nimbys along its route. There is plenty of room on the surface for the tunnel to run, although some over or under passes may have been necessary. It is the huge expense of tunnelling so much of the route to Birmingham that has made the costs so large. If you add up the mileage, it must be getting on for the length of the Channel Tunnel. Costs were piled into this project by politicians not engineers.

[Macc]

Once-in-a-lifetime civil engineering project. Once it's done, it's done. Congratulations to everyone involved.

[GrahamWoodward-wwzf]

Fantastic engineering which will be in use for 200 years plus.

[guygfm]

Fab very complicated job so good to see the progress. Thanks for sharing

[chrismason]

A fascinating insight into these tunnel works

[simoncroft]

Excellent video and good length at last! Thanks.

[Mr_ZeroFuel]

Mind blowing feat of engineering! Well done to everyone involved.

[JanetRowthorn]

This video and the project is Incredible, all the moaning about how long it takes and then you see the real issues faced like excavating beside an essential trainline. How on earth they navigate a brand new train line through the complex crowded London areas must takes years of planning and incredible skill to get it right.

[shaunwest]

Congratulations, stunning work, incredible achievement and engineering 👌👍

[Helga-vugq]

your passion for your content is infectious, keep it up!

[RichardBacon-hx]

Excellent video that's a decent length. Small suggestion, put a thumb nail map in the corner showing locations rather than the big map

[grahamross]

Take a sip every time someone says "sharft" in this highly informative and beautifully shot vid.
Keep sipping til they reach Euston or Manchester.

[uzha]

Seems like 90% of the stretch could've been built as surface rail, to save a good amount of money... Something that wouldn't significantly impact the neighborhood, given that rail line already exists and just needs a little additional land for widening. That's what engineers from the yesteryear would've said I suppose... today we abhor noise and hold backyards sacred on wholly new levels 🤷

[TheMak]

Everything HS2 is 50% complete, even the length it’s running

[GatesAion]

I remember back in 2008 when they started building the HS2 or at least getting ready and it's still not even done, if this was japan it'll be done on budget

[davidconnor]

Shafting, on a scale of shafting, that has not been seen since shafting began. Everyone gets the opportunity to get a shaft, be shafted and ensure anyone who misses out on a shaft, gets a good shot at a jolly good shafting at some time soon, hopefully, once all the major shafting has been completed, on this enormous root…👍🏼.. in it