I am very doubtfull indeed about this.
The passenger carying pods will run in a tube containing vaccuum, and will therefore need to be pressure tight and carry a reserve of air, and means of removing carbon dioxide, More like a spacecraft than a train. Any failure of the pressurisation will quickly suffocate the passengers.
And how are thousands of miles of vaccuum tube to be kept air tight ? Even a slight imperfection will destroy the vaccuum. Any defect in a tube below water, or below the water table on land will fill the tube with water.
The capsules presumably cant move through water, so everyone suffocates in the sealed capasule, or excapes and drowns.

Very silly idea IMHO^▸ (in my humble opinion).

Yes, I said "promoter" to avoid argument from any pedant whom might point out some subtle difference "HS2 Ltd" and "HS2" but they are in effect the same thing.

Anything published by HS2^▸ (The next High Speed line(s)) promoters is probably a bit optimistic, but is most unlikely to contain significant factual errors.

One must be careful to differentiate between the carbon emissions produced by USE of a railway or other infrastructure, and those produced by BUILDING the infrastructure.

The emissions produced by USE of HS2^▸ (The next High Speed line(s)) are unknown, since they will largely depend on the future carbon intensity of yet to be produced electricity. Some repairs and replacements of infrastructure will be needed, but the future carbon intensity of concrete, steel, copper, and other materials is unknown.

The missions produced by BUILDING HS2 could be estimated from amounts of different materials used in construction and the carbon intensity thereof. Figures would only be estimates.

Anti HST^▸ (High Speed Train) groups have claimed that flying or driving or driving would be greener than HS2, but they tend to cheat by including the carbon emissions from building HS2, but for air or road transport including only the fuel burnt by the vehicles.
If the carbon cost building HS2 is to be counted, then they should also include the carbon costs of building roads and airports.

The liquid air energy storage system shows considerable promise and may yet be adopted on a large scale.
A considerable amount of low grade heat is produced during liquefaction, and unless some paying demand exists for this heat it represents a loss.
Thermal sesalination of seawater, grain drying, and heated greenhouses have been suggested.

When air is liqueified, there will be a small fraction of gas that wont condense. Mainly argon with small amounts of helium, and other rare gases. It might be worth extracting the helium when other supplies become short.
Liquifying air to extract the minute proportion of helium would be hopelessly uneconomic, but when large volumes are being liquified in any case, the economics are different.
Liquid nitrogen and liquid oxygen could be produced as an ancillary business to energy storage.

Yes, it was a terrible tragedy and "seems" more recent than 16 years ago.
There was a great deal of bad luck in this case. A collision between a lightweight road vehicle and an HST^▸ (High Speed Train) might, under other circumstances, be survivable, but not in this case.

I recall considerable ill informed media comment about this event.

Escape by the survivors was aided by the provision of emergency light sticks, as was first aid treatment. I had previously suggested to GWR^▸ (Great Western Railway) that these light sticks should be provided. I know not if provision was as a result of my suggestion, or was already in hand.

There is not AT PRESENT any regular surplus of renewably generated electricity even in windy weather. Inspection of the gridwatch site will show that overnight and in windy weather, that natural gas is still being burnt for electricity generation.
However with increasing numbers of wind turbines, the day will come when there WILL BE a surplus at night in windy weather.
With more solar power being installed, a daytime surplus in mild weather and bright sun is a future possibility at weekends when demand is less.

It is therefore well to plan for FUTURE surpluses and how to either use the surplus in some productive way, or to store it.

Yes, to transport 100* tons of passengers requires about 1,000* tons of train and that is presuming reasonably full trains. Allowing for lightly loaded services such as INTO London in the evening peak, and off peak services in general, 10,000 tons of train for 100 tons of passengers might be more reasonable.

To move 100 tons of freight is unlikely to need more than 100 tons of train, empty weight, or 200 tons with the 100 ton payload. Or say 300 tons of train on average allowing for most wagons being empty one way.

Passenger trains also consume energy for heating, cooling, and lighting. Most freight has no such needs.

*Due to the many variables, no great accuracy can be claimed in this, but as approximations.
100 tons of passengers=about 1000 people including clothing and hand luggage.
To convey 1000 people needs about two full length IETs^▸ (Intercity Express Train) (seating capacity varies in different version but is about 500)
Full length IETs weigh ABOUT 500 tons with passengers. (varies a bit depending on version, and on 5+5 versus 9 car)

Figures for other types of train will vary but should be "in the same ball park"

At present, wind power is meeting about 4% of our electricity demand, better than not having that 4% but a small contribution.
CCGT^▸ (Combined Cycle Gas Turbine) (combined cycle gas turbine) plant is meeting about 40% of demand.
Yesterday, some power was from OCGT^▸ (Open Cycle Gas Turbine) (open cycle gas turbine) an expensive way of generating electricity. The main merits of OCGT plant are low capital cost, quick to build, and quick starting.
Some OCGT plant starts automatically in case of a sudden drop in grid frequency. Some can burn light distilate oil in an emergency, but natural gas is the usuall fuel.

Our significant wind and solar generating capacity have reduced the amount of coal and natural gas used for power generation, thereby reducing carbon emmisions and reducing the need for natural gas imports.
This later point is important becuase the UK^▸ (United Kingdom) is now very reliant on natural gas imports, AND we now have less gas storage capacity than a few years ago.
Any event that significantly reduced gas imports for more than a week or two would have most serious consequences.

However as recent events have shown, we dont have adequate plans for cold but calm weather.
Battery storage helps, but is not yet sufficient.
Pumped storage helps but is not sufficient and oportunities for expansion are limited.
Natural gas burning is the main alternative at present. Burning natural gas intermittantly in calm weather is better than for base load generation. (reduced carbon emmisions, reduced foreign exchange used, our limited storage will last longer)
The existing nuclear power station at Hinkly point is unlikely to be available for this winter.

Something new to do on Christmas day might be watch on TV the arguments, legal disputes, and other news about the American election.
It seems a reasonable forecast that arguments and disputes will still be underway by then. Christmas would be good time for both sides to point out that God is on their side, as a careful study of the scriptures will show.

Hopefully an electric van will be used to transport the scooters rather than petrol or diesel fueled.

I have no intention of organising any illegal gathering, and I hope and expect to comply with the other rules.

No sphopping apart from home deliveries.
I expect to visit neighbours, but think that this is allowed. I will be the only visitor and we will meet outside, or if raining in an open sided gazebo.
Transport by horse* drawn cart, so in the open air and over 2 meters distant from the driver.

Vet visit booked for health check and vaccinations of pet cat, but booked for the day before the lockdown starts.

*Readers will be glad to know that it is a large strong horse.

I suspect that compliance will be very poor.
Significant numbers of people are planning to ignore or evade the restrictions.

Look at thenumber of raves, street parties and other illegal gatherings, that are illegal at present but are continueing.

I know of one large family who are going to meet for Christmas and believe that they have found a legal loophole to permit this.

Ran through stop blocks at end of the line, and rather than falling a considerable distance to the ground or water below, the front vehicle was left suspended on a whale sculpture !

Driver taken to hospital for checks but reported to be unhurt.
No passengers on board.

https://www.bbc.co.uk/news/world-europe-54780430