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Gareth Dennis Profile picture
@GarethDennis
Sep 5, 2021 • 32 tweets • 12 min read • Read on X
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The last leg! Paris to York! 😭

(terrible PTI of course, as with all high speed European trains)
So little left of our 4000km epic from south east to north west Europe...
Well, this is true... I'm already getting giddy about passing through it, as I always do.
We got up to some stuff in our half-day here...
Genuinely forgot we'd booked Standard Premier, and I have to say I'm glad of it... Not least for the (now eaten and definitely tasty) grub! Thanks @Eurostar!
Though @Eurostar - can you please fix the overhead screens (they are stuck on this) as I'd like to know how fast we are going and these e320s are Faraday cages for GPS!
Lovely sliding table action though, @SiemensMobility... No expense spared here! 🏆
oh oh oh oH OH OH OH OOOOOH 🚇 #chunnel
To my mind the Channel Tunnel is one of Europe’s greatest engineering achievements. So passing through it always gets me excited.

I picked out a beefy selection of highlights about its construction, history and current operations for @RAIL back in 2019:
garethdennis.medium.com/channel-tunnel…
(Shame about the fash fencing that we wouldn't need if we just provided unlimited legal routes for people who want to live in the UK to get into our country without risking their lives.)
Oh, and I threaded a TV show about it if that's the sort of thing you fancy (lots of nice archive footage):
le BIG BOI
So there's no overheads (incidentally the first heavy rail running lines without overheads I'm seeing for this whole trip) but the trains are still electric? How confusing.
This view is definitely more fun in the other direction...
(we've probably already arrived by the time these post, I'll continue shortly)
Having been on quite a few miles of high speed line over the last week, I've just realised that a major constituent cost element of new UK rail alignments must be that WE BURY THEM ALL IN MASSIVE CUTTINGS that cost the earth (literally)... 😖
(Ed: check this)
IT'S THE EYE OF THE NEEDLE!
(or would be if there wasn't a sound barrier)
Here's a bad picture of the Thurrock Viaduct working its way under and over the Queen Elizabeth crossing and the Dartford Tunnel respectively (not sure if in that order though):
We've arrived (at 6pm, only two hours after leaving Paris)... And what an arrival it is! 😍
Thanks @Eurostar and @StPancrasInt for welcoming us back after the better part of 4000km of travel... And in pretty decent style, too 🤩
From one glorious place to another, and this one does feel a bit more like home... Also this thread is catching up with real time again ⏳
This thread is back in real-time again, and whilst this @LNER #Azuma isn't reaching 186mph, we are travelling at a higher average speed than we were on the Frecciarossa...

125mph plus tight timetabling plus rapid station passes makes a lot of difference!
See!

(This thread covered our Rome to Paris leg.)
The ride quality is *much* worse here though, it has to be said. Sorry everyone at Hitachi/Network Rail, but my bum (and this glass of orange juice) doesn't lie.
Also: masks just aren't a thing here anymore, I see 😔
Frecciarossa 1000 loo doors!
Again, here's the reference:
Worth pointing out that the ride quality isn't a safety issue - there's a fifty-times increase in track tolerance requirements at the 200km/h threshold which will account for a lot of the difference.

(though I'd love to compare the East and West Coast Main Lines 😈)
We're nearly in York, which means I obviously have to dedicate all of this to my wonderful, wise and unwearying travelling companion, who has been dealing with my irrepressible and chaotic nonsense not just over the last three weeks, but for 6 years now.

Thanks, @JankovicDina 😘
It's (a very busy) York station! Long time, no see!
Finally, after much adventuring, we end both today and the whole holiday just as we started it... On @tierscooters to our corner of York 🛴💨

Time for bed. Thanks for following!

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More from @GarethDennis

Gareth Dennis Profile picture
Jan 25
Here I'm in agreement - welding rails of two different ages together is completely routine and safe, otherwise you'd have to replace all rails all at once every time.

Crucially, though - it's the new rail that failed adjacent to the weld!
Deleted previous extra bit as I've spotted something that I need to verify.

The new rail has been confirmed as R350HT as seen in the image.

However, the old rail appears to be R260. If this is the case, then a specialist weld is required and that doesn't appear to be the case. Image
Image
Image
Image
It's very difficult to validate this from the available images, but it would certainly be good to know what grade the older rails to the south of the weld are. Anyone with better photos or access to the material records?
Read 19 tweets
Gareth Dennis Profile picture
Jan 21
A bit of discussion about this detached bogie being a cause rather than an outcome of the Adamuz crash. It's essentially impossible for a bogie to be released from a moving train without that train already having been derailed. A huge piece of debris, seen by a photographer for The New York Times, appeared to have flown roughly 900 feet from the tracks, landing next to a stream running through a steep-sided gully below the railway.
One of the crashed trains with what appears to be a section of the undercarriage missing.
It's being reported that this was found around 275m from the railway - the potentially 400km/h closing speed of the two trains when they collided will have easily created enough energy to launch the Iryo bogie that distance. another shot of the bogie half covered in a ditch
Despite their mass, bogies are often thrown loose during high energy derailments. The location of this bogie and the section of the train it departed from will help investigators establish the precise trajectories of the derailed vehicles and the energies involved.
Read 21 tweets
Gareth Dennis Profile picture
Jan 19
I think we're now able to build a pretty clear picture of the most likely mechanism of the train crash at Adamuz in Spain. Image
Image
Image
Image
1️⃣
The northbound Madrid train (a red Frecciarossa 1000 operated by Iryo) passes over a rail weld, likely fractured within its heat-affected zone, that breaks under the impact of the passing train.
2️⃣
The first 5 cars of the 8-car train pass safely over the break, but repeated impacts turn a break into a catastrophic rail failure, and the 3 rear cars of the northbound train are derailed as the rail shatters. Image
Read 9 tweets
Gareth Dennis Profile picture
Dec 29, 2025
From what I understand, the Interoceánico train that tragically derailed killing 13 people yesterday WAS NOT the High Speed Train of the type I refer to in the video below. An awful lot of people in my mentions jumping to conclusions without knowing the facts.
The challenge for Mexico is that they have no independent investigating body like the NTSB or RAIB. The pressure now needs to be applied to ensure that the investigation is thorough and transparent - or even better that the chance is taken to create an new body.
Further clarity: there is nothing "high speed" about the Tren Interoceánico system. The HST, or "High Speed Train" is specifically the original name of the formation of locomotives and passenger cars that was introduced in GB in the 1970s, capable of running up to 125mph.
Read 8 tweets
Gareth Dennis Profile picture
Aug 30, 2024
Let's post some receipts, for the benefit of anyone attempting to defend @LordPeterHendy, @SYSTRA_UKIRL and @NetworkRail's actions in some way. Because I have a folder of this stuff. Image
Off the bat, I am going to make an apology and say that I won't do alt text for this thread as it is too onerous - however if you require alt text for accessibility reasons, please just DM me and I can send you the whole lot directly.
So, a few highlights. First up, back in June when I was sorting out my employment with @SYSTRA_UKIRL, I had already made clear statements that I would be continuing my advocacy for rail and my role as a writer and public expert on transport.
Read 30 tweets
Gareth Dennis Profile picture
Nov 12, 2022
I don't know who needs to hear it, but giving public sector workers a decent above-inflation pay rise is probably one of the quickest ways to turn the UK economy around.
(I do know who needs to hear it, it's Labour shadow cabinet members.)
All the people replying to this saying this will increase inflation: you are wrong and your ignorance is very dangerous. Parrot your Friedman propaganda elsewhere.
theconversation.com/why-wages-shou…
Read 5 tweets

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