This question may seem silly. But what exactly do you do with your bags when riding the rails throughout Europe? Do they consistently have overhead racks/shelves? Are there storage compartments? What do you do with your bags if you go to the restroom or the dining/snack car? We will each have only a carry-on size rolling bag and accompanying tote/shoulder bag. Thanks for any insight you can share!
Every train I have ever seen has somewhere to put your bag, usually an overhead rack, but, unless the train is crowded, I put it on the seat next to me. I use a convertible carryon. If I'm traveling alone, I take it to the bathroom with me.
I'll add to what Lee said.
Like you, and Lee, I do carry on only. I bring a small wire/cable and lock my bag to the rack. It's nothing a determined thief couldn't get past, but it makes my bag a less likely target for a grab and dash at a stop (someone grabs your bag and jumps off the car just as the doors close and the train starts going).
Large bags more often need to be stored at the end of the car near the door.
A very good question with no good answer. Depends on what your luggage is.
There are overhead racks suitable for small bags and most smaller carryons. Large bags must be stowed in racks at the end of each car.
When you leave your seat I just leave my bag. I carry my day bag with me that has my camera and such, but it's silly to lug around luggage to the WC or lounge. I use travel locks to prevent someone from rifling through and found it unlikely someone would have the chance to actually take the bag. Avoid being away from your seat at station stops - otherwise thieves have nowhere to go.
If your bag is at the end of the car, put it at the end you are facing so you can keep watch. If not, just keep an eye out at station stops.
For our experience the probability of theft while the train is moving is extremely low. We store the day bags overhead and lock 'em to the rack. Often just use a strap and don't brother with a cable unless I am going to be gone for extended period of time. A slightly higher reported risk is someone walking through the car and grabbing a bag and jumping off the train as it starts to leave the station. I think that is a possibility but have never seen or heard from anyone who has had that happen. However, when we put bags in the storage bins, which we do frequently, I do use the cable lock to secure the bags to something or lacking something secure the bags to each other. And, of course, the usual advice is not to keep anything of great value in any of these bags. When we are going to be gone from a seats for awhile, will take the day bag with the camera, etc.
A side note -- we notice that locals toss their bags in the storage bins or on the overhead racks with little additional security. My guess is that they know it is not a big problem.
We store our bags at the end of the car and use cable locks to secure them and keep our day back packs (which every opening is locked) with us. Never had a problem.
BTW, we do keep a close eye on the luggage at train stops even though they are locked.
Depends on what type of train you are riding. There's usually adequate room on the overhead rack for ICE trains, less so on regional commuter lines.