I mean, where it snows, if there's snow over them.

This seems pretty unlikely to me ... some problems:

- Dirt and snow covering them up (they talk about brushes on the rear of the train cleaning them!)
- Protective glass top becoming scratched and more opaque over time
- Smashed panels from flying rocks propelled by the high speed trains (maybe only for very low speed routes?)
- Inefficient collection of the electricity (long and lossy power transmission lines)

The article talks about using the electricity to run the trains that pass over them, that the trains usually run during the day when the panels would be active. That would avoid the transmission loss, but the electronics to share the power with trains as they run over the panels ... seems dicey to this non-EE. It'd be cool if it works, but I wouldn't count on it