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Discussion (91 Comments)Read Original on HackerNews
You can do a pilot test of solar panels anywhere and call it a success, but the real test is scaling it up in an economically viable way compared to alternatives. None of that was tested.
Putting panels in a line is the worst arrangement. Just put them on roof tops or fields and keep it to places where they don’t have to be armored and reinforced.
However, I agree that putting solar panels in between or near rails will increase the cost of maintenance: the technicians will need to travel longer times to the work site, and now they also need to be certified to work near railroads.
Just normal-ass solar is already safe proven and effective. Why do we need to remix it when there are still so many easy wins to be achieved?
If there's a single downside I'm not sure what it is.
Should have many of the same drawbacks, with 2 big differences:
1. Trains not driving directly on the panels' surface (which makes solar roadways a bad idea in any case). And
2. Trains on their own track, so the 'road surface' conditions of the panels (rain, snow etc) don't matter safety-wise.
That said: imho there's still so many spaces better suited to put solar panels, that between train tracks is among the last places I'd go for. Especially if it requires custom-design panels.
Before I read the article I was thinking the electricity from the panels would power the trains but doesn't sound like the output is enough.
> in one year, the project has produced around 16,000 kWh.
160 kWh per meter.
Still not sold on the idea. For something with a 20+ year life span, the initial deployment effort seems kind of irrelevant and should be better located somewhere that does not require ongoing activity. Train ballast requires replacement every N years which is going to require ripping up all of those panels.
Dropping panels in place is not the hard part. Getting all of that electricity back to a connection point is one of the many problems created by this idea.
Putting panels in a multiple kilometer long end-to-end row is very inefficient compared to rectangular layouts that can be clustered around connection points.
You can put panels on anything and generate power for a couple years.
This system was only 18kW. That’s less than what we put on some residential houses. They didn’t address any of the hard parts like a transmission system capable of scaling up along a linear row of panels extending kilometers long.
> Solar panels have gotten so cheap that it might not be as important to install them in perfect conditions, and other factors like real estate, ease of maintenance, access to the grid come into play in interesting ways.
They had to use special panels for this, not the cheap ones you know. Any installation in an area like this requires reinforced and protected panels, which are more expensive than what you’re thinking.
You did identify some of the problems: Maintenance on this is terrible. They’re not going to shut down train routes to fix problems with the solar, so when something breaks it’s probably broken for years until a maintenance window can shut down transpiration.
Access to grid is terrible. You can’t re-use the train power lines, so I guess we’re running new transmission lines? A linear array is the worst possible configuration for a solar array because it maximizes the transmission distance and starts to require high voltage equipment to work.
Would you ever think it would be a good idea if someone suggested we go put solar panels out in the middle of nowhere between towns? Or would you agree it’s better to put them close to the towns on unused space like rooftops where they can feed directly into local loads? I think the visual of putting these on train tracks is misleading a lot of people into thinking we’re getting something for free when really this is an absurdly expensive way to place and connect solar panels.
But, putting panels between the rails seems foolhardy to me too.
The manufacturer claims that durability should not be an issue. Time will tell.
I would expect that the solar panels impact the efficiency at least somewhat but apparently not enough to cause real and enough issues for the SBB or perhaps they see ways to improve this in the future.
On paper, this should be pretty cheap. Normally, you need some mounting infrastructure to put the panels on, land preparation, etc. In this case, the train track provides the supporting infrastructure. You can bring in the panels via train wagons. Installation should be pretty quick and straightforward. And for cleaning, you could just do that from a rail wagon as well. Not having to truck in anything seems like it should be a big bonus here.
Durability might actually be fine. Solar panels are pretty reliable. And it's not like the train is in direct contact with the panels. The vibrations might be a challenge but presumably that would have shown up in the trials. It's something you could engineer solutions for. And so what if a small amount of panels fail?
But a train company practically always has running trains when the sun is shining. So they wouldn’t need to worry about disabling and losing money on the panels.
The real challenge is economically connecting the panels to a rail substation.
And getting approval to widen the right of way, where it’s even physically possible, and issues around flora suppression.
The most common Swiss electric (4/4) typicaly maxes at 6100kw requiring up to 34km of track.
Switzeraland has about 5000km of track and 180 is about 200, so a million kilowatts if all the track has solar panels.
Assuming 3000kw per locomotive and 100% efficiency [2], that's 300 electrical locomotives running simultaneously. The Swiss fleet is about four times that.
---
Of course I am no expert.
[1] https://en.wikipedia.org/wiki/List_of_stock_used_by_Swiss_Fe...
[2] and ignoring the 10 per year efficiency loss of the panels mentioned in the article
If you want hard numbers, SBB used 1685GWh for passenger trains in 2025 [0].
The bigger problem with this idea is solar in Switzerland. It's fantastic during the summer but close to nonexistent during the winter [1]. Trains need to run year-round, so you'd need to overbuild solar monstrously to power SBB during the winter, or you'd need to solve seasonal electricity storage, which isn't easy. Pumped hydro is great but Switzerland has already built about as many artificial alpine lakes as the population is likely to tolerate.
[0]: https://reporting.sbb.ch/en/sustainability?=&years=5,6,7,1&s...
[1]: https://energiedashboard.admin.ch/strom/produktion
3000kw is about 1/2 power for the most common Swiss electric engines.
And peak demand determines grid size.
Remains to be seen, considering how much snake oil there is in the solar market (but to be fair, this makes more sense than solar roads). A news article summary of a press release isn't proof of much.
I have tried entrepreneurial stuff twice before, in my 20s, though without much success. Having ideas good enough to get investors interested is a sign that perhaps I should have another go at it.
But I will agree that the idea has proven marketing merit. This is a class of truly top tier snake oil. The solar roadways people continue to go unbelievably far on almost the same grift.
It’s just kicking up dust and dripping lubricant onto it.
Maybe this makes sense. I’m deeply sceptical. Especially when you could just be putting vertical panels to the sides.
I wonder if the benefits are legal/jurisdiction/political. The total amount of track they could install this on is huge, and it doesn't seem like something that will be disagreeable on the local level. It could just be the easiest place to put it to deal with property law and zoning etc.
Another political benefit is that it means work for a very large number of jurisdictions, as there are suitable tracks just about everywhere.
This is far from an of course. There were idiots trying to do solar roads a few years ago. The math didn't pencil out.
> the railway was fitted with 48 specially-designed solar panels with a combined power of 18 kWp.
18 kW is less than what gets installed on a lot of houses. It took 100 meters to do this. The farther the panels get from the interconnect, the higher the losses along the line.
It’s easy to set up 18kW of panels in one spot. Covering an entire railway with panels would require a different transmission setup to get the power back to somewhere useful.
I really wish we could just forget all of these ideas to put solar panels in places that are highly trafficked and serving double duty. Just put them in unused space that isn’t used for anything else: Rooftops, empty fields, or over parking garages. I often get downvoted for saying this because a lot of people like these ideas of putting solar panels in space that they see, like sidewalks or roads or railways, but we have so much unused space that isn’t near foot traffic, road traffic, or railways that is so much cheaper and easier to use for solar. These projects usually turn into political grifts to get government funding because the ideas are not economically viable alternatives.
Thankfully, Switzerland has lots of meters of railway.
> Covering an entire railway with panels would require a different transmission setup to get the power back to somewhere useful.
There's caternary on 99% of Swiss rail, every few dozen meters, that already transmits power.
The linear meters of railway are nothing compared to the square meters of rooftops. Putting panels in a long row is the maximally worst arrangement you can come up with.
> There's caternary on 99% of Swiss rail, every few dozen meters, that already transmits power.
I guarantee this wasn’t oversized to accommodate power transmission duties, too.
It’s also high voltage line. The solar setup would need additional and expensive high voltage equipment to interface with the line and to work within the design parameters of a line that was designed to deliver to the train, not carry extra power.
You could put the panels anywhere else and connect them normally to the grid like every other installation.
Its sole purpose is power transmission, to the trains.
Switzerland runs on 15 kV catenary voltage. Transformers suitable for that kind of voltage cost a lot of money.
Panels on the sides ot trains might be a better solution.
WHY?! Dave from eevblog did the math and it's bad
Did we really fill up all the area on top of roofs, parkings lots, industrial areas, etc., and we're running out, and we have to put solar cells on railroads?
I guess it is easier to control the deployment since they own the railroads.
There are also a lot of vertical sound proofing barriers that could be equipped with panels.
This trial tied the panels to the grid, but they want to connect it to railway substations or directly in to the trains power system for the traction motors.
Making the power only available for trains.
And never at night, as is typical with solar panels.
https://lenews.ch/2026/07/04/new-nuclear-plants-a-difficult-...
On the Solar Rail
For there's much we just don't know
So farewell with a kiss
Then it's fast for the mist
Till we're sleeping in the cold below
Hard: the tracks on which we roam
Panels when the dark's not coming
Feel the weight of what we tow