Is there a special train ticket for frankfurt to koln then koln to cochem?

On the weekend, you can use a €37 Schönes-Wochenende-Ticket, but you will have to take regional trains.

Frankfurt, Köln, and Cochem are in three different Länder. There is not a single ticket you can use.

If you are traveling on a weekday:
Purchase local (RMV = Rhein-Main-Verkehrsverbund) point-point tickets from FRA to Mainz at €3,70 per person. You can get these from an RMV automat in the Regionalbahnhof.
For Mainz to Bonn and Bonn to Cochem, purchase a Rheinland-Pfalz-Ticket for €27. This you can also purchase in the Regionalbahnhof, at a DB automat.
For Bonn to Köln and back to Bonn, you can use a VRS (Verkehrverbund-Rhein-Sieg) Preisstufe 4 Regio Tagesticket (Day ticket) for €20,60. You might be able to purchase this ticket online at www.vrs-info.de. Otherwise you would probably have to get off at the station at Bonn, purchase it, then take the next train to Köln. On the way back, you wouldn't have to stop in Bonn.

Total price for 2 people would be €55.

Thanks Lee you truly are the expert on Germany! lol. Well sorry I responded before on my other question about the mosel tickets before I saw this one. I don't know about the Cologne ticket from Frank. because I did see the fast ICE ticket which gets there in 1 hour but we have to pre-purchase it ahead of time and I'm concerned about the plane being delayed on the way over there. Do you think the tickets you metioned here would take too long to get there? What do you think?

According to the German Rail website, most train connections between FRA and Köln take about 3½ to 4 hours, assuming a 20-30 minute stop in Bonn to buy your VRS Tagesticket.

I would be very wary of planning to use a discount offer right after your scheduled arrival. I was an hour late into FRA last November. By the time you allow extra time between schedule flight arrival and your train, so you don't miss the train, you can do it just about as fast with regional trains.

I might just do the Rhein cruise the day you arrive and use a RL-P-Ticket and the VRS tickets to go to Köln on a later day.

Lee, quick question... Is the train station in frankfurt called frankfurt main or
Frankfurt(M) Flughafen Regionalbf or Frankfurt airport? also is it Koln hbf, or Koln something else? confused.

The main train station within the city of Frankfurt is call Frankfurt(M) Hbf (Hauptbahnhof, or main station).

There are two train stations at the airport. The Frankfurt(M) Flughafen Regionalbahnhof (abbr. Regionalbf) is under the building across the street from Terminal 1. It handles the S-Bahn between Mainz/Wiesbaden and Frankfurt and mostly regional trains. You get to it by going down stairs just inside the streetside wall of the terminal, then through a passageway under the street. The Frankfurt(M) Flughafen Fernbahnhof (Fern=far, long distance trains) is located out beyond the building across the street. It handles express trains (ICE/EC/IC). You get to it by going up the escalators to the 2nd floor mezzanine of the terminal hall, across a pedestrian bridge over the access road, and down a hallway through the 2nd story of the building.

If you are using the local RMV tickets from the airport to Mainz, you should use the Regionalbahnhof. Note that there are two S-Bahn lines through the Regionalbf. They run from track (Gleis) 3 every 15 minutes, alternating between S8 and S9. S9, at 12 & 42 minutes after, goes just to the Wiesbaden Hbf; S8, at 27 and 57 minutes after, goes first to the Mainz Hbf, then to the Wiesbaden Hbf. In the other direction, both S8 & S9 go to the Frankfurt Hbf, usually from track 1 to the Frankfurt(M) Hbf tief or underground station.

The main station in Köln (or Koeln) is called the Köln Hbf. It is sometimes attached to the word "Dom" (cathedral) because it is right next to the Cologne Cathedral, or "Innenstadt" (inner city).

BTW, you will sometimes see Frankfurt(Main). That's for the Main River, pr. "Mine", not for the main station.