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Comment by danhor | Hacker News Reader

While hydrogen EMUs were first used in germany in planned service (with battery EMUs coming into service later this year), it seems that BEMUs might be more mature right now. The only HEMU being used right now is the iLint, and it has been in development for many years while the first "real" deployment is plagued with issues (to be fair, not all of them stemming from the iLint itself). Meanwhile it seems that BEMUs are being offered by nearly every company, with trains from three different manufacturers starting service in the next 12 months.

Hydrogen will probably see some use in railways, but more for freight and long-distance applications, mostly outside of Germany. I wouldn't be surprised if a large part of freight and long distance service in the US ran with hydrogen, with commuter trains mostly using batteries and conventional overhead electrification.

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I just don't see it. It's just such a pain in the ass to store and handle. Locomotives are actually a better case for batteries than most, because you could keep the batteries in a secondary car, much like a steam locomotive tender, that can easily be swapped out on a siding when needed in about 10 minutes... or just chain as many together as you need for the trip.

Trains, especially freight trains, aren't that weight sensitive, since they tend to mostly roll along at the same speed.

Such trains could be fitted with a pantograph and operate directly off OHLE when possible. Actually, don't recall the class but I'm fairly sure the UK has a variant of one it's commuter EMU with a small built in batter. The route it travels has a few miles without wires where is impractical to add wires so it uses batterys to cover that gap.

Not being weight sensitive is the very important key point. It means trains of the future could use some non-lithium battery chemistry.

Likely sodium-ion, which is projected to be significantly cheaper due to abundant materials, safer due to its chemistry, more tolerant to hot/cold weather, and it's main drawback of lower energy density isn't a big deal to trains.

I think the power requirements for the train might be the limiting factor tho. It's not quite the rocket equation but you can't just drain the whole battery pack on a 3% incline and get 15-30% back on the decline.

a 4000 HP train is ~ 2,000 kWatts. The average diesel-electric locomotive uses 3.5-4 kwh / mile of electricity (according to chatgpt). So to go 500 miles we're looking at 53,000lbs / 26.7 tons of _just_ battery (doubled up weight to account for non lithium). The locomotive itself can weigh 120-220 tons. A freight railcar can weigh about 100tons.

For a yard locomotive where they are just moving things around this could be super useful. For hauling freight around it's a potential? You're basically losing a freight car of cargo per 500 miles.

And I would really want this thing to be NOT made of lithium ion cuz if the train derailed it would be fairly destructive.[

25 tons in a 5,000ton ore train is a rounding error.

A typical locomotive carries approximately 5,000 gallons of diesel fuel, which at 7lbs a gallon is already 17 tons, not counting the weight of the tanks.

The diesel engines will be even heavier (and they're Diesel Electric, so they already have electric traction motors, and the related electrical equipment).

Train's don't haul just one car, they haul dozens or even hundreds.

You need something like 500 tons of batteries, even with superior efficiency numbers taken into account, to match the energy of 5,000 gallons of fuel. It is actually significant if people did the math correctly.

That certainly changes things somewhat, but I still think railroads would jump on it if it meant, say, 1/3rd less maintenance and half the fuel costs. The move to tier 4 emissions is/was a big deal. They’re starting to have to use DPFs and SCR.

Your quick calc actually seems to show how viable battery locomotives are, not how viable they aren't.

25t of batteries and you save all of the hassle and maintenance of combustion.

Please don't trust chatGPT for this. It is likely off by a factor of 10:

http://reasonrail.blogspot.com/2015/09/a-cost-to-benefit-ana...

It looks like 22-66 kWh/mile, depending on size of train.

The problem is that the cost of batteries pretty quickly undermine the cost savings of not fully electrifying the rail. If it is just a few miles, it makes no sense to have a fleet of battery trains for those short trips.

There is no justification for BEMUs in this case because you can simply use direct electrification. The rails are already electrified except for short sections. It's actually a pretty rare scenario to ever need battery powered trains.

In reality, this is one of the silliest stories of the year. I'm guessing this is probably some kind of subsidy harvesting scam.

More than 40% of the german railway network isn't electrified, which supports around around 10% of of traffic. Simply looking at https://openrailwaymap.org/ shows you just how many small branch lines and less significant lines don't have overhead power for dozens of kilometers.

This means that for large parts of the network there is some traffic, but far from enough to justify electrification which costs around 1M€/km (and, with some tunnels, might even mean expanding the tunnel diameter). There is a reason DMUs are widely used for these lines, and expectations are that BEMUs might be even cheaper to run.

More lines should be electrified, but expecting it to cover everything is not realistic nor economically justifiable. See https://vm.baden-wuerttemberg.de/fileadmin/redaktion/m-mvi/i... for a study on how to run non-electrified lines in Baden-Württemberg which comes to result that BEMUs are cheaper for around half of the lines that full electrification.

I'm not aware of BEMUs getting some special subsidy (meanwhile electrification is heavily subsidised, IMHO for good reasons), looking from the perspective of the ones financing and specifying the operations.

For those totally unelectrified sections, you need something like hydrogen trains. This allows you to go hundreds of miles without power. But battery trains require catenaries at both ends for charging anyways. And the limited range of battery trains implies that the unpowered sections must be very short, and could easily be electrified instead.

Which is why this decision is nonsensical and seems like some kind of subsidy related scam. Whatever the motivation, it cannot be based in rational thought.

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