Add half an hour if you need to buy a ticket - long queues and/or ineffective ticket-machines at the upstairs station at FRA. much better to order tickets online from www.db.de

And keep an eye on the German news about the train-drivers' industrial dispute. The courts ruled the mainline drivers couldn't go on strike, but...

Upstairs at platform 1 at Koeln is the 1st-class lounge, accessible with a 1st-class ticket UNLESS it's a 1st class rail-pass which they won't recognize.