Here are a few views of the Pittsburgh Light Rail system, including the downtown subway. I bet most of you didn't know we had a subway here in Pittsburgh, albeit a short one. Still, it's very cool with 4 underground stations and a portion of it actually passes through a tunnel under the Allegheny River. During downtown events, games at Heinz Field and PNC Park, and at rush hour, it is heavily used as can be seen in the second photograph.
I always felt an articulated light rail vehicle would be an outstanding model for the three rail O gauge market, and since they are heavily used in Europe, could be used by MTH for both their American and European markets.