The Stuttgart Rack Railway, the Zacke, is public transport that behaves like a small mountain railway. It climbs from Marienplatz toward Degerloch on a steep urban line, giving quick views over Stuttgart's bowl-shaped centre.
Ride it as a practical outing rather than a museum piece. Ordinary transit tickets work, bikes have their own uphill trailer on suitable services, and the line pairs nicely with a walk around Degerloch or a loop using Stuttgart's other hillside transport.