For context: I travel between Cologne and a city near Gütersloh, which means switching trains in Hamm. The National Express trains I'm talking about are the RB

For context: I travel between Cologne and a city near Gütersloh, which means switching trains in Hamm. The National Express trains I'm talking about are the RB48 and RE7. There are two ways to get to Hamm besides the ICE: RE7 (National Express) and RE1 (DB Regio). Although the RE1 is a double-decker, most of the extra space is wasted on first class seating. They do have toilets but they're tiny and usually extremely filthy. Maybe I'm particularly unlucky but as I said, the average train seems to have at least one door marked as out of order at any given time. I've actually seen an RE1 leave Hamm with an open door once (I was too surprised to take a picture though). The main reason I prefer the RE7 is the ability to charge my laptop (allowing me to get actual work done). I also find the trains much nicer in general. The only exception was during Karneval because there is sadly no ban on drinking alcohol on regional trains (unlike trams in Cologne). My worst experiences with DB Regio have been on RB and S trains though. I had a daily from Cologne commute to Neuss for a year and a half and none of the trains had toilets even though some of them still had signage directing you to non-existent toilets. Officially they were no longer offering toilets on S trains because travel times were short enough that passengers don't need them -- which certainly comforted me while routinely spending roughly an hour on those damn trains.