If electricity is too expensive, then there's no way they can afford hydrogen.  Unless it's the sort of hydrogen that's made from natural gas, in which case they might as well install LPG tanks on the trains.

This thread raises another interesting question for me, how are the users charged for electricity. To run a train I assume you have to pay some form of rail access/usage charge, maybe based on tonne milage. If I am using diesel traction I can source my own diesel at whatever the best rate I can find is. If I am using electric traction how am I billed? Does the locomotive have a consumption meter? Is the charge again based on some tonne milage calculation? Who sets the charge per kWh, do I get a choice of supplier?

Here, Switzerland, it is somewhat different. The railways have their own 16 2/3 Hz hydro electric stations and their own 16 2/3 Hz grid so the costs/charges are internal. There are some 50 Hz - 16 2/3 Hz converter stations.

https://company.sbb.ch/en/sbb-as-business-partner/services-rus/energy/sustainable-energy.html

Diesel can generate quite a lot of pollution:

https://youtu.be/uOj6gPwkiXg

In the UK, electric trains get their electricity from Network. Network Rail charges the train companies for the electricity they use. There are two ways that Network Rail can measure how much electricity each train uses: by guessing or by checking. Guessing is based on things like how heavy, fast, and far the train goes, and where it travels. Checking is done by using meters on the train that record how much electricity the train takes from the wires above it. In 2010, some train companies started using meters instead of guessing, which means they pay for what they actually use. This is better as it shows how much electricity each train uses and makes the train companies want to use less electricity and pollute less. But it is also hard because it needs meters on every train and making sure the data is correct. There are also some problems in measuring the electricity from the wires, such as losing some power, having different frequencies, and having different phases.
Network Rail sets the price for each unit of electricity (kWh) for electric trains with the help of ORR. The price changes depending on the time of day, the season, and the region. The price also includes a part for carbon cost, which is how much pollution is caused by making electricity for the railway. The price is updated every year based on changes in electricity prices and carbon costs.
Electric train companies have to use the electricity from Network Rail through the wires above them. They cannot choose a different supplier for their electricity. But they can choose to buy their electricity from Network Rail at either a fixed or a variable price. A fixed price means that the train company pays the same price per unit of electricity for a certain period of time, no matter how much the electricity prices or carbon costs change. A variable price means that the train company pays a different price per unit of electricity that changes with the electricity prices or carbon costs.

In Switzerland, as you said, it is different. The railways have their own power stations that use water to make electricity and their own power grid that uses a different frequency (16 2/3 Hz) than the rest of the country (50 Hz). So they do not have to pay anyone else for their electricity. There are some stations that can change the frequency from 50 Hz to 16 2/3 Hz if they need to connect to the national grid. The Swiss railways also use meters on their trains to measure how much electricity they use and charge each train company based on their actual usage. The price per unit of electricity is set by Swissgrid, which is the company that runs the national grid, and includes a part for using the network and a part for supplying the energy.

In Wales this is already happening: news.tfw.wales/.../uks-first-hybrid-train-enters-service-on-borderlands-line

AMK said:

I think that DB Cargo should look for other ways to make its trains run without diesel or biofuels, such as using electricity, hydrogen or batteries. I also think that DB Cargo should tell everyone how much CO2 it makes and how much it reduces, and be honest about its environmental goals and actions.

However, it could also be argued that, in a free market economy, that since rail freight has considerable lower emissions per ton-mile (e.g. ref below), then to reduce CO2 emission what is more important right now is that rail freight companies keep their costs as low as possible (and their flexibility as high as possible) to encourage freight transfer from other modes to rail.

Example data: https://www.cbo.gov/system/files/2022-12/58566-co2-emissions-transportation.pdf 

Then, once a higher proportion is on rail, it does of course become more important to encourage reduction in rail CO2 emissions (which is happening anyway) - it moves from a second order effect to a first order effect.

I agree that shifting stuff by train is better for the planet than shifting them by lorry, less fuel and make less pollution. One train can carry as much as 110 lorries. But I don’t think that making trains cheaper and quicker is enough to make more people use them to shift their stuff. There are other things that count, like availability and quality of rail infrastructure, how well the trains work in different countries, the reliability and punctuality of rail services, loyalty of rail freight operators and more. These things make trains more decent and fit in the market, and they need brass and new ideas from both the government and the businesses.

The economical position taking in all expected running costs over the 20 year life cycle of the locomotives is critical in establishing whether to use electric or diesel hybrid.  If DB analsis is correct then HS2 needs to immediately reassessed and the electrification of the line deferred but rail track installed quickly before costs rise due to delays. 

According to what I’ve found on the web, DB Cargo has ordered up to 400 Siemens hybrid trains that can switch between electric and diesel modes depending on if there’s any wires above them. This could cut down on how much fuel they use and how much pollution they chuck out, as well as make them more handy and trusty.

As for HS2, I think that it’s a tricky and touchy project that has good and bad points. I don’t have enough knowledge or skill to say if they should put off wiring it up or not.

Totally agree.

AMK said:

DB Cargo has ordered up to 400 Siemens hybrid trains

The Siemens Vectron - sadly, as I understand it, not usable in the UK as they are to EU loading gauge.