Discontiuous electrification: is it really the best way forward?

[HSTEd]

It is unlikely freight operators will order brand new diesel-only locomotives, bi-modes can handle discontinuous electrification but class 90s and such like can’t. This might be problematic.

Well the likely future of freight operations is just the continuation of the Class 66 forever.

 

[Technologist]

Because the necessary batteries weren't proven at the time the contract was awarded - some of the later electric 80x units do have have emergency batteries.

There is an Arthur C Clarke quote "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong."

If something is demonstrated it is possible, the lack of demonstration or a choice by any actor not to do something does not mean that anything is undesirable or not possible. One of the issues with batteries is that as a sector it is moving at about 10X the speed of rail decision making cycles.

Rail decision making needs to enter the 21st century, obviously first it will have to enter the 20th....

At Amazon they have the concept of 1 and 2 way doors, a 2 way door is a decision that you can walk back from and/or modify. Decisions on 2 way doors need to get made close to the issue and the level of certainty and review on the decision needs to be reduced, it is more important for 2 way decisions to be made quickly and in higher numbers than it is to get them all right. 1 way doors are more difficult as once committed they are difficult or impossible to reverse, these need significant scrutiny. This process also means that if you can structure projects and purchases as 2 way doors you can move faster so there is a strong incentive to do this.

The applicability of this to the BEMU discussion is that it needs to be understood that batteries are a fast moving market with generally good positive trends on cost reduction and performance improvement. This means that stuff should be procured so that improved tech can be more readily inserted both during production runs and in service, ultimately that all needs flexible processes at every level and a more can do attitude around risk and a willingness to look at other sectors who have incorporated new technologies well. The inherent savings associated with improved technology will in the long term more than offset any issues with technology risk. Compare and contrast NASA SLS/Starliner and SpaceX.

UK rail needs to be a lot more ambitious, if people are used to driving around in 600bhp EVs with excellent refinement and tech trains are going to seem very old hat again and we'll see the same sort of relative decline we did after WWII when people compared a Jag mk1, Citroen DS or any 50's American car to a steam train and it was obvious what the future was.

== Doublepost prevention - post automatically merged: 8 Jan 2025 ==

I've already written my rambling essay so I'll just leave this as a reminder - you can't beat the energy efficiency of not carrying your power plant on board. This is why the victorian kept trying to build cable and wierd vacuum pipe railways before electrification had been developed.

We all accept that MML should be wired "cus it's intensively used or something" but we need other railway lines to become intensivly used even if they don't currently reach whatever threshold for wiring you all have been agreeing on. We need those lines to increase their capacity because we need people to stop using cars whether they be ICE or EV. A like for like swap of engines to batteries will do little to improve the transport sector's sustainability. Cars do more damage than just their tailpipes. Likewise railway electrification is so much more than no longer having diesel engines on trains.

This thread (and tbh many more across transport discourse) seems to view OLE as a method of getting rid of tailpipe emissions on rail vehicles- which is a potential option but too much more expensive and disruptive than battery traction. This view ignores the circa 100 years before policymakers had any interest in climate anything where railways from fully private to fully public actively chosen to electrify. If no one cared about emissions, why did they do it?

I’m not sure that we can use arguments that we did something 100 years ago to provide any guidance today. Lithium ion batteries have only had practical applications for about 30 years and until 12 years ago were limited to portable electronics. Once the Model S came out LIon batteries dropped off a cliff in terms of price due to the vast quantities of batteries that were needed. Lithium ion batteries are now down to around $50 per kwh and while some of this is due to Chinese oversupply and nobody is making profits this downward trend is not going to stop any time soon.

At current never mind future battery prices battery packs are basically in the noise for the overall price of a train. If we have a 400 tonne train with 5% of its mass being an lithium ion battery pack, that is a 3MWh LFP pack with a manufacturing cost of about £250,000. That would allow it to travel well over 100 miles off the wires. It would also allow the train to accelerate with a power of 24,000bhp, which if you wanted to replicate with a OHLE train would mean that you’d need to massively reinforce the system. Installing a motor system that could deliver 24,000bhp would be considered unnecessary expense, but there is another way of expressing that system, 24 Tesla Model S’s, those drive units have a cost price of about $75,000, again noise in the context of a train. Obviously people could come in an start talking about durability and reliability requirements, to which I would say:

1: Automotive kit has much more development money and more in service hours than railway kit.
2: Our train would be powered on every axle by at least 1 motor, we can afford to lose motors without noticing
3: Duty cycle assumptions go out the window, this thing never accelerates for more than 90 seconds and can climb a hill of any grade at a fraction of full throttle. These motors have a gentle life.
4: Who cares if I need to replace motors at some point in the service life.

Up shot is that BEMUs are getting to the point where there additional cost is trivial, meaning that installing OHLE on a whole route will make less and less sense over time.

We cannot make long term first principles based arguments as to what is effective engineering. For example if I went over a 120 year old bridge I might find it was a steel lattice type, the bridge would be lighter and more structurally efficient than an modern pre-cast concrete bridge. However when it was built, labour was cheap and efficient due to lower safety standards, the parts were small and manually handleable and could be brought to site on a cart or small lorry. Today we can use massive cranes and lorries to bring pre-cast sections to site and it needs far less inspections and maintenance. The concrete structure is not efficient but it is more effective, in 20 years from now we might find that robotics and AI means that we start building more lattice work structures as on-site labour is suddenly much cheaper and maintenance and inspection can be automated.

If battery technology advances in the future could lines be de-electrified with OLE and 3rd rail removed?

Not sure it is realistic to expect all diesel trains to be replaced in 20 years time, although I don't think any more DMUs or diesels locomotives should be built.

How long did the last steam trains operate for, I suspect that BEMU will very rapidly undercut diesel to the degree that it’s worth scrapping relatively new diesel trains rather than maintaining a diesel infrastructure/burning fuel. BEV cars passed ICE cars in lifecycle costs a few years ago now and if we include Chinese imports it's possible to get BEVs that are cheaper than equivalent ICE cars at below average new car sales price points. Historically ICE cars beat steam and electric cars by the mid 1910's, diesel trains start appearing in the 1920's and 1930's, steam gets a stay of execution due to WWII but following it they are phased out in 20 years.

If we project forward 10 years or so a purpose built BEMU express train might be able to allow 10-15% of its mass to be battery and that battery pack could be at around 250wh/kg (it could be that today but I suspect the economics will favour cyclic life and up front cost rather than pure performance). This train could operate for hundreds of miles off wire even at high speed, I would image that further growth of OHLE would be limited to areas where a moving charger made more sense than fixed ones. When it comes to renew OHLE potentially it could get taken down where its costs are higher and where there is enough remaining OHLE and fixed chargers to keep the trains charged.