Scheduled train service on the branch line from Wächtersbach to Bad Orb was discontinued some time ago. So if you want to go to Bad Orb by public transport you have to get off the train at Wächtersbach and take a bus from there.
The track to Bad Orb still exists, but it has been converted to narrow gauge (first photo) and is used occasionally for museum trains pulled by a small steam engine.
The former railway station at Bad Orb (second photo) is now a restaurant with the town's largest beer garden, featuring a children's playground so the children can occupy themselves while their parents are eating and drinking.
1. Narrow gauge railroad track to Bad Orb (less than half its original width)
2. Former railway station in Bad Orb
Bad Orb is easy to reach by bicycle from Frankfurt. Just take the regional cycling route R3, which follows the banks of the Main River to and through Frankfurt and then goes up the Kinzig Valley starting in Hanau. From the R3 there is a five kilometer cycling route going off to the right (east) to Bad Orb (second photo).
Like most of the regional cycling routes around here, the R3 is clearly signposted except in cities and towns, where the one crucial signpost tends to be missing just when you need it. The first time I tried following the R3 through the city of Hanau I took a wrong turn and ended up in a very tiresome place called Wolfgang, which is off in some other direction entirely.
Fortunately they have a train station there, so I just took my bike on the train for a few stops up the valley, to make up for lost time.
Update 2007: On my August 2007 trip to Bad Orb I learned that parts of the R3 can be impassable if there is high water and the Kinzig River overflows its banks. The place in the second photo, for instance, is quite low and I couldn't even get there this time. Fortunately I met some nice people who could tell me how to get around the flooded places and up to higher ground.
Update 2009: There is now an alternative "high water route" in some parts of the valley (third photo).
1. On the bicycle route to Bad Orb
2. Junction between the R3 and the Bad Orb bicycle route
3. New alternative "high water route" 2009
All the regional trains have bicycle compartments so you can take your bicycle with you to wherever you want to start cycling from.
In the area served by the Rhine-Main Transit Authority "RMV" it does not cost extra to take your bike along, but in other parts of Germany you sometimes need a supplementary ticket for your bike.
The photo shows the bicycle compartment in the lower deck one of the red double-decker Regional Express trains.
It isn't always this empty. On a nice day you often get twenty or more bicycles in a train like this.
There is no longer any train service all the way to Bad Orb, by the way. The closest you can get to there by train is Wächtersbach.