What always fascinates me is how the engineering requirements change the faster you go. All these weird physics things that the Victorian engineers would never have had the need to even consider.

Different hard hat colours mean different thing, general people have white and site managers have black. Blue is specially reserved for those who need help with their gloves.

Dad just walked in as I started watching this and wondered why I was watching a video with Rob in it! Turns out he worked with him, he thinks when he was on cross rail- but my dad was a H&S manager for many railway projects, so could be another project. What a small world!

Delays in government planning and cutting back the Northern ends of HS2 I have some problems with, but the actual engineers on the ground when left to do their job are doing fantastic work.

The level of engineering on HS2 is seriously impressive, a huge viaduct followed almost immediately by a 16km twin tunnel 🤯👏, all around 200mph on this section, looks stunning too, just a shame, planning etc has taken this long since the inception of the idea of the line. Suspect this will be forgotten when the benefits are realised though, like most other projects

I know this area very well this has decimated the whole valley the railway line is at head height with the trees where swans, owls and other bird life fly. This should have been a tunnel but oh! That would have been to expensive.

I pass this twice a day whilst I commute to and from work. Its great to see a bit more of an in depth video of what is actually going on. From the outside it just looks like a giant concrete factory. Which it is, to be fair. I look forward to more videos on this topic. Good work Geoff!

The contributors were tremendously knowledgeable.superb vid thanks.

Been watching this bridge go up in thirty second intervals at 100mph from the Chiltern line over quite a few years now. Really cool to get a closer look.

I live right next to this in Hillingdon but regularly commute through here. Over the years I’ve seen it go from nothing to what it is now, and as beautiful as it looks, what really isn’t shown is the disruption that has been caused as a result with closed roads, traffic, work traffic.

Far more educational than almost all of the official HS2 films. I'm all for more engineers sharing science-based insights with your viewers. Thanks!

As someone who lives in Chalfont St. Peter and has always been interested in railway and architecture, having this built on my doorstep is one of the best things to happen to my local area in my lifetime!

@4:25 Geoff "it's like a motorway". Rob "eff off - it's a cool bridge" !

Lovely to see some nice Bridge work again. Your safety equipment is far nicer than Mine from the late 70s and 80s. Lighter and more comfortable.

The useful analogy of the porous portal would be the suppressor on a rifle, which reduces the noise produced by the bullet leaving the barrel. It works in exactly the same manner.

Can't wait till this railway is operational

The scale of HS2 is absolutely bonkers. To think this is just one of goodness knows how many construction sites along its length is pretty mindblowing.

This would be history about 8 + years later 😮!! Then we come back and say, WOW THIS IS HOW THEY CONSTRUCT THE HS2!!

HS2 is absolutely mind blowing, like HS1 and Channel Tunnel. Thanks Geoff!

I live in the area in Harefield so been watching it come along very informative video and shows you what a massive engineering project it is thanks Geoff!

Thats a very good looking bridge, very aesthetically pleasing

Thanks for this Geoff; amazing progress and about time that we saw the new railway rising up.

I like the efficiency of your videos.

I went to have a look myself last week and you have made a fantastic video to go with my visit, thank you Geoff, brilliant timing...👍👍👍

love your vids geoff, learnt so much more about the tube/ trains from you =)

Gorgeous engineering. Makes me proud.

Great engineering, going to be amazing to look at when it's finished

As both a train and a canal fan, it’s interesting watching the differing opinions on HS2. :)

Yet another great insider video from you, always a pleasure

Another great video Geoff. Always look forward to them. Looking forward to travelling to UK.

I went to view a house near Denham/ Iver a few weeks ago and F-me the traffic in that area was abysmal. Just queues and queues of lorries, temporary lights, roadworks. The road network round there is an example of how motorway building has destroyed local communities (M25/ M40/ A25 all coming together and all its slip roads etc/ a lot of duel carriageways and huge roundabouts) and building this has compounded the issue. Anyway, I crawled past in traffic where they were building the viaduct, and it’s so impressive to see, a marvel of modern civil engineering. However no way would I ever let my children out on their bikes on those super congested roads, so we’re not moving to that area.

When you can go from Manchester to London in just over an hour (down from over 2 hours) all the opposition to HS2 will go quiet and be forgotten. Amazing project!

Hi Geoff, Wow what a impressive video of the HS2 which is massive project, the huge Viaduct is absolutely brilliant with how the deck gets laid, all the engineers on site are doing a amazing job…..once again many thanks for sharing with all of us, you are truly a huge inspiration to us all! 😊👍

Nice, I was lucky enough to have a tour around the site back in November, it amazes me how far the viaduct has come since then, you can barely see that launching girder from the road

Looks huge! Can't wait to ride it some day.

Been down that road. On my way to The Coy Carp pub. The Viaduct looks amazing

There is an incredible vista that takes in the majority of the Colne Valley from The Old Orchard Pub in Harefield. There's no getting around the fact that the works have turned an area of outstanding beauty into an eyesore. I really really hope that in its completed state I can learn to love the engineering and find some kind of peace with the structure, because right now I'm far from that place. Skipping stones? Its a concrete behemoth.

Thanks!

Awesome Video Geoff

PPE check, Gloves right side out. Thanks for referencing that again.

I got the feeling Rob wasn't amused by the glove shenanigans! 😂 Great vid though thanks Geoff - it's fascinating to see these big engineering projects coming together.

I'm desperately trying to write a comment that is not automatically axed. I was trying to give some info about two examples of porous portals, one between France and Spain, the other in Northeastern France. They are the "Perthus tunnel" and the "Tunnel de Saverne". Both are easily viewable from the satellite view of GMaps and are existing POI's with these titles. The Perthus tunnel is located on the high-speed line between Perpignan and Figueres and is an international tunnel. The Tunnel de Saverne is located 30 kilometers (as the crows fly) North-West of Strasbourg on the LGV Est between Paris and Strasbourg. They respectively see trains running at 300 and 320 kph. They both have different types of porous portals, and both have twin tunnels. The Perthus tunnel has multiple "windows" that increase in size from the tunnel outward to the end of the portal. The Saverne tunnel has two sets of two large vertical piston relief and dilution vents on each portal and both portals have a "crown" or "cap" of tube bars that also helps to brake and dilute shock waves. Voilà

Fascinating Geoff, great to see progress, your videos and those of HS2, help explain not just what's going on, the promise of a whole new additional transport network for the future, but just how many people around the country are reliant now and into the future for their livelihoods on this project, a fact seemingly lost to some of the present Government,

What a stunning structure...!

that was really interesting thanks geoff.

I love the fact that they built a temporary concrete factory to service both the TBMs and the bridge construction machine. I hope that the government reverses it's decision to throttle back on HS2 (or that we get a different government that agrees to extend HS2 to the East of England and Scotland) so that the temporary factory can be moved up north and reassembled (instead of just being scrapped). I also hope that something useful can be done with that access deck that the van drove onto. I think it could be an awesome cycle path between towns in the area. But, if it's not allowed to stay, I hope it can be used to make a cycle route and walking route somewhere else.

Really impressive

Love these little updates Geoff. Great access.

I hope you do a video on Curzon Station in Birmingham, there's a lot going on and you will be able to ask how they are incorporating the Grade I listed building from 1838 into the final design.

Good Job 👍

The Man in Seat 61 in the minibus? When worlds collide!

Great vid 🎉🎉

Who couldn't love a Geoff Marshall video?

Great video…. Please can you do a video quickly about the loss of ticket offices. We need to get out there the catastrophe loss to the the railway they will be if they go. People have done videos about this who have been on your channel but you have the large subscriber base and contacts at network rail and the Train Operating Companies to really get the message out there make a difference and help convince the government that this is a really bad idea and you have the ability to spread the word…. Cheers Geoff

Great video Geoff - keep them coming. I support the idea of HS2 but know that the vision will not be realised for probably 50 years. We only have to look at the promise that HS1 and the Channel Tunnel provided yet I still have to fly to Switzerland on holiday rather than take a through train from London to Zurich.

Its wild the level of design and engineering in this project, definitely could be done chesper with less infrastructure but this is all out

I saw the stretch going over the Grand Union Canal and the lake east of that a couple of weeks ago - 4:30ish

Nice vid Geoff!

It is a impressive viaduct, great video

Can’t wait

Geoff you have put your gloves on the right way

Gosh it looks like a huge project.

you can see where the money is going, the design of the viaduct is elegant, in Spain where they rolled out 1000s of miles of HS rail the viaducts are very rough and ready..and cheaper

I like your videos Geoff

Great!

If you visit the denham grove hotel you can get a good view of the bridge construction from their grounds

I've been waiting for the HS2 update great video keep up with the great work

300k subs quite an achievement!

MORE HS2, MORE HS2.

“But how did he get run over?” “We couldn’t see the bright orange man’s gloves…!”

Seeing the viaduct being constructed here is the first time I’ve felt how real this project is now becoming. Tunnel breakthroughs are all very well but they’re all pretty similar and underground so you don’t get as much of a feel for the progress made compared to this. Great video.

Nice vid

Geoff I love ur vids

The whole thing is incredible but look how long it’ll take

I’m not a total fan of HS2, tbh, a bit of an HS2 Sceptic but, I love viaducts and that’s looking kike it’s going to be a lovely one

Blimey, the Trans Pennine Express upgrade has got out of hand! Oh? It's a different Colne Valley? As you were then.

Incredible piece of engineering- hope to one day travel on the line!

i cant wait to meet you at Thanet parkway

Are you going to do anything on the east west rail project thats reconnecting oxford to cambridge?

Your hs2 hat is the cool one.

A video quickly giving an overview of the progress along the length of the HS2 route would be very much appreciated. 😊

the company I work for has been working on some of the projects, I wonder if I can convince my boss I need to go down and see it for...technological purposes lol

Cannot wait until High Speed 3 is built 😅

Very C😎😎l & exciting!!! 🙂🚂🚂🚂

i wish these videos were longer

Good morning.

Speakign of PPE my Uncle used to be in electrical sales and went to a clients workplace once in Alberta and they gave him a Cowboy hat shaped Hard hat as part of his PPE that he got to keep afterwords.

The two analogies referred to about the Colne Valley Viaduct are pertinent. Geoff's observation of the structure (without parapets and all the other paraphernalia), 'it's like a motorway...cars are going to be here', is a rebuttal to claims of aesthetic elegance in the architect's alleged assertion that the design drew inspiration from the idea of skipping stones across a lake. Perhaps the claim for a stone-skipping analogy should be made with some caution - it may be read as a mandate for protesters to have a bit of fun by doing that, indulging in the popular summer evening activity, First to smash an HS2 train window wins

This construction of HS2 is going to take as long to open to service as the Bakerloo line extension to Lewisham, provided it even goes ahead

Hey Geoff its TransportForLuka here, i've commneted many times on your videos and you have replied to many of them, my old channel name used to be called "SecuroServ" that was an ugly name from a game i used but i changes it now to an excellent name that really suits the transport content i post now, anyways good job with this one you made, love your videos as always, you got me into transport so I shall thank you, and one day i want to make a parody of secrets of the underground called "secrets of the buses" so when i do post it be sure to watch, it would mean the world to me if you enjoyed it, but i won't be making it any time soon though so stay tuned!

What holds each segment to the previous segment - at least until they meet in the middle?

wow

Such a small country, high speed rail should criss cross the whole country easily

I tried to find this launching girder a few weeks back. I went to Denham and walked along the brambly "path" along the A412. I found the viaduct, but the launching girder had moved on since, and I got a bit caught out by the rural buses. Where is the launching girder now? Is it on or near publicly accessible land and can I get there without driving?

Great engineering… gloves

And there's me thinking momentarily that there's a new link going through Essex/Suffolk...

Can you restart your London's lost railways series and make a video on the Kensington to Richmond line through Shepherds Bush and Hammersmith, I can collab if you need me to, I am quite an expert on that line. Great video as always

Apologies for being off topic but I wasn't sure how else to get in touch. As a regular user of the Elizabeth Line I am becoming increasingly frustrated by the daily experience of cancellations and last minute rerouting of trains which make a mockery of the much vaunted improved service. Any chance of a video exploring this shambles?

I was a bit shocked to find HS2 had already made it to Colne at the Yorks / Lancs border, but no.

I guess the structure I can see. From the m25 is to do with the viaduct ?