I agree garratt15a. Unfortunately I didn't go on board - the tour I was on didn't include her, and there wasn't time for an independent visit. Things that struck me about her from the outside were the wide separation of the funnels with the bridge between them, the smart little gazebos on the paddle-boxes, the impressive rudder, and the arched guard-beams along with a stout structure aft of the after funnel that reminded me of a tugboat. Probably nothing remarkable to a sailor, but I'm just a curious landlubber.
This is almost certainly a preserved River Rhine steam tugboat. I saw many of them when I visited Konigswinter am Rhein in 1956. They were hugely impressive, battling upstream against the Rhine's powerful flow.
Thank you vitalspark. Regensburg is on the Danube, but I dare say Danube and Rhine tugboats would closely resemble each other, even in the days before the two rivers were linked by the Rhine-Main-Danube Canal.
Thanks, Ian, for the info. I had no idea Regensburg was on the Danube. I'm sure you are right, and what works on the Rhine would work equally well on the Danube. They are impressive craft, and it was a treat to watch them working. I think the reason they favoured paddlers was their shallower draught compared to screw-propelled vessels.