I have been to Charleroi (it's a large town in Belgium) a couple of times before cheap flights were available from Dublin to Cologne. I used to get Ryanair flights to Charleroi and go on with the Thalys which was cheap back then.
Anyway, I always remember looking at their strange pre-metro system and thinking about it this evening it struck me that Charleroi built a system it didn't actually need while Dublin continually fails to build a similar system that is desperately needed. Strange world.
I found a cool thread on Skyscrapercity with some great pics of the never opened stretch of line, complete with (now vandalised stations) and illuminated signals! These signals have been presumably switched on for over 20 years, despite no trams ever having passed them. What a waste of electricity!
All in all, quite a fascinating little system.