Not certain that age is such a problem, HSTs^▸ (High Speed Train) are older than that and were in intensive main line use until recently, some still are.
I doubt that a complete new royal train would be needed anytime soon.
The odd new vehicle if required could be converted from existing stock.
I doubt that HM would be very keen on other people using the more private vehicles of the Royal train, It should however be possible to remove these vehicles and store them, substituting a couple of other vehicles for use by the PM or other VIPs.
The staff vehicles, storage areas, kitchen car, dining car and some others could reasonably be used, simply detach the dedicated sleepers used by Royalty.

Anyone know what happened to the cats ? Hope that they were OK.

I count myself as a "moderate Royalist". I support the Royal family, largely out of a sense of tradition. Having a Royal family that has been in existence for longer than most countries is one thing that sets us apart from dodgy banana republics.
I do not however have any interest in royal "tittle tattle" and the latest "exclusive revelations" as found in Tabloid newspapers.

I am pleased to see members of the Royal family touring the country in the Royal train. It is a boost to morale and almost certainly greener than flying or driving.

The fixed annual costs of maintaining the Royal train are indeed considerable, but it could therefore be argued that it should be used MORE, since these fixed costs are then less per mile.
Many of the variable costs are wages or salaries of the many persons required for the security and comfort of Royalty, these are not strictly railway costs as they would be required also for air or road transport.

Closure by stealth.
GWR^▸ (Great Western Railway) can not drop the sleeper on a whim as it is a franchise requirement. However frequent closures, part closures and downgrades will help by reducing patronage to the point where dropping it is easier to justify.

And when it does run, making it a connecting service via Reading does not help either.

Surveys will show that;

1) Only a small percentage of passengers use it.
2) Most customers would prefer something else.
3) An at seat sleeping arrangement would be preferable.

The survey may have already been done.

1= A welcome development, dangerous in the wrong hands, but so is printing, as is teaching the lower classes to read.
2= Arguable either way. Undeniably useful, but consider the climate, noise, congestion, and fatal accidents.
3= Most regrettable.
4= Even more regrettable. Bring back tavern cars.

Young sir, you again tend to exagerate a little.
Taunton has moved with the times and many new innovations may be seen, including;

Electric lights, even in working class homes.
Shops with an upstairs.
Motor omnibuses have largely displaced horses.
Patent water closets are in general use.
The latest London fashions may be obtained in the larger stores.
Fine modern public houses, that serve chilled foreign lager beer as well as good honest ale. Some even serve imported wine.

More likely to be service at ones seat I suspect, than a buffet.

Glad to see the Royal train being used. Almost certainly greener than air or road transport. And as has been said the train is probably safer than the alternatives, against both accidents and deliberate attack.
I wonder if travel via Taunton is to be included ? In the past Taunton has been generally avoided as historically it was known for anti-royalist views.
It used to be the practice to close all curtains or blinds on the Royal train if it was unavoidably routed via Taunton.

More recently however the Royal train has visited the West Somerset Railway, so perhaps ideas have changed.

I agree. It is also worth remembering that even before the challenges resulting from the pandemic, that a great many shops, and bars, cafes, and restaurants went bust each year. I have heard but can not substantiate, that over half of new small busineses fail in the first year.
It is easy for those whose new enterprise has failed, to blame this on pedestrianisation, too much traffic, unfair competition, brexit, failure to achieve brexit, left wing politics, right wing politics, etc.

On balance I think that less traffic is good for trade. Also safer for pedestrians, cyclists, and the like. The reduction in carbon emmisions is also helpful in meeting the various targets.

I would prefer to see pedestrian zones enforced by fines, including draconian fines for repeat offenders. I have misgivings about physical barriers as the work of the emergency services is thereby held up.

From the passengers point of view, this might well be a backward step. Apart from the risk of the complex message chain not working, it seems likely that the passengers would have to arrive at least 5 and perhaps 10 minutes before the advertised time of departure.
So a journey from a request stop has in effect been extended by five or ten minutes.

5 calls not only suggests about 5 minutes required, but also gives 5 opportunities for the message to be lost, delayed, misrouted, misunderstood or otherwise fail to have the desired result.
"Hello, this is ABC control. Press button one if this call is about an emergency. 2 for our charity work. 3 for our environmental mission statement. 4 to hear about job opportunities with us. 5 for accounts. 6 for anything else."
Caller then presses 6.

"We are helping other customers at present and the average waiting time is 18 minutes. You may prefer to call back at a less busy time, or alternatively visit out website where most enquiries can be dealt with"

I have previously suggested a simple passenger operated push button that lights a warning lamp beside the track. Red, green or yellow lights are effectively ruled out to avoid confusion with ordinary signals.
I have previously suggested a rapid flashing white light.
I doubt that misuse would be a great problem in the remote locations involved.

That is very sad, and I hope that the cats were properly cared for before being reunited with their owners.
If unwanted or abandoned, I hope that an animal rescue charity was able to care for the poor cats.

When comparing rail travel to air, I suspect that rail may perform batter than suggested above.
I would not expect the locomotive to run at full rated power for long, 6.5 Mw when accelerating or ascending inclines, certainly, but much less as an average. Within living memory, a single large stem locomotive with a power output of about 1 Mw was used on sleepers, two such locos at the most.
I am not convinced that the energy used to heat a sleeper train should be counted, If the passenger had flown instead then they would have spent an extra night in their heated home, or in a heated hotel.

As regards the source of the electricity for the electric train, we are indeed some way from 100% renewably generated electricity, but 50% or more is well within sight. Jet fuel is 100% fossil fuel, and likely to remain so.
I have high hopes for an increased percentage of renewably generated electricity.

I agree, the overspending and delays are regrettable, but leaving the project three quarters built and substantially unusable was not a realistic option.

We know not what the future holds, but I fully expect that Crossrail will be well used when it eventually opens. For decades, rising passenger numbers within London or indeed further afield have simply resulted in worse overcrowding rather than in more capacity.
Nice to see some extra capacity actually being built.

You can not be "green" and still support air travel.
If we are serious about the climate emergency, we need to fly and drive a lot less. Rail is the obvious alternative.

I would in general support a ban on flights to places that can be reached in 12 hours by train.
Perhaps with the provision of sleeper trains for popular journeys of over about 9 hours.

Much more use needs to made of the Channel tunnel IMHO^▸ (in my humble opinion) for long distance passenger services. Northern parts of the UK^▸ (United Kingdom) to much of Europe SHOULD be doable by train, sleeper trains in some cases. In practice flying is the default choice because there are no through trains from most of the UK to mainland Europe.
Changing in London AND again in Paris is perceived, with some justification, as being expensive and complicated, and increases the chances of delays or other c0ck ups.

Banning most short haul flights would also mean an end to airport expansion, present facilities should suffice.

A 16 hour journey by three different trains from say Newcastle to Southern Europe wont attract many holidsymakers. A 12 hour  journey by through sleeper train could prove popular if afforable and reliable.

Whilst the odd breakdown and delay is inevetible, being on a through train with food, drink, and sleeper cabins is far, far better than being stuck at an airport or station.