A point of note - this isn't JUST a tourist attraction, but actually part of Pittsburgh's port authority (i.e. Public transit).
I take this regularly to get downtown (I live nearby) and the experience never gets old. It always amuses me to watch first time riders on this admittedly creaky incline train (think old wooden roller coaster sound with doors that shut loudly & abruptly). There are the beautiful views out the window of course, but make sure to look up as there both cars have really cool old light fixtures as well.
Cash (exact change) or connect card (port authority's reloadable fare card)