Join Date: Aug 2006
Location: MUC (home), DUS (office), XXX (customer)
Programs: LH, AB, SPG, CC, Sixt, EC
Posts: 6,334
I had to commute between DUS airport and CGN city every day for about two years and I used the train...
From DUS airport Railway Station (connected by SkyTrain to the Terminal A/B/C) are at least two IR (Inter Regio - don't be afraid - it just stops 4 times between CGN and DUS - not at every tree) trains per hour to Cologne...
If they are on schedule, they leave at X.31 and X.51 from track 4.... You are at CGN main station at X.15 the following hour (the "X.31 train from DUS) and at X.35 the following hour for the other train. So, that's exactly 45 minutes...
Round ticket is less than 20 EUR, you get them at all ticket machines (upstairs, not at the platform!!!! - cash prefered, credit cards don't work once in a while) or at the counter directly at the Skytrain exit (long lines)
There are further trains to CGN as well, all leaving from track 4as well , like the a little bit faster ICE (Inter City Express) or IC (Inter City) (both make 2 stops between DUS and CGN) but they are more expensive, they don't commute that often and they are not really more convenient.
By the way, don't count on the conductor not showing up and getting a ticket on board... If you get a nasty conductor, you'll have to pay the "no ticket" fare of 40 EUR (one-way)... Aditionally if they don't like your ID, they let the police check you... So, try to avoid that...
For further questions, don't hesitate to send me a PM...