I see the article says that they propose special solar panel cleaning trains that will pass along the track and wash the panels. That's all very well, but it sounds to me like this cleaning will need to be undertaken very frequently, imposing a significant overhead. Wouldn't surprise me if the extra expense of such cleaning will exceed the revenue generated by the panels!
I mean, there are so many things that would deposit dirt or other detritus on such panels:
- Falling leaves. A lot of British suburban lines run in cuttings, with significant tree coverage on the embankments either side, leading to the infamous train delays due to "leaves on the line". Rainfall alone ain't going to clear those.
- Rail-head treatment trains (RHTT) - a method of mitigating the above - blast dirt everywhere. If you have ever seen one, you'll know how exceedingly dirty the train itself gets. Now imagine that muck covering the panels. Every RHTT would need to be followed by a solar panel cleaning train!
- Any rail grinding would blast the surface of the panels with a red hot shower of sparks. I'm sure even the most robust of glass surfaces couldn't help but end up with some pitting and un-washable slag stuck to it.
- They would never be able to use them on any lines frequented by steam trains, due to the potential danger of fireboxes dropping hot ashes.
They also mention that "parking rails" are a candidate location. I don't see why, as such places tend to be overgrown with weeds in sunny seasons, due to their infrequent use. Would be yet another maintenance overhead, as the weeds would need to be kept down.
Their test installation in Germany was supposed to have been completed last year. Would be interesting to see whether they have had very much success with it.