Is there a power supply on European trains for laptops? You know, something to plug into, and if so, what connector is used?
The first class seats on fast trains like Eurostar (both the Italian and London-Paris), ICE, Thalys, TGV, and other fast trains in other countries have outlets.
They use regular European two-prong outlets
I rode in 2nd class on a Eurocity (EC) train in Germany, and it had a power connector. I think it was the type of receptacle that accepts two round pins. I'm sure it wasn't US, and I couldn't have used it unless it was the two pin type.
I found that most of the trains that I travelled in didn't have an outlet next to my seat, even in first class except for a few like the ones mentioned earlier. But, most seem to have an outlet in the toilet for electric razors and such. One guy I was travelling with had to sit in the toilet to charge up his cell phone.
Glad I wasn't on a train with that guy. Not very considerate, tying up the toilet just to charge your cell phone...