When I'm traveling solo on train and have my pack above me with everything in it that I carry on my back (approx 25lb), what do I do if I need to use the WC? Even if I lock my pack to the rack, anyone can get into it. In the past, I've been lucky enough to have trustworthy looking strangers nearby to ask to keep an eye on it. But what if the only person nearby looks sketchy or in general, what to do if I am needing to walk to the next compartment or dining car/etc?
Sally, I often travel solo, so have to deal with the same issue. I usually travel with a main Pack, Daypack and Camera bag. I never visit the restaurant car, as that would mean having to take the whole kit with me. I usually pick up a sandwich / Panini, bottle of water or juice and a snack at the station before departure, so that I don't have to buy the pricey rail food from the cart. There are usually lots of food outlets in the stations, and some of the food is really good! For quick trips to the WC, I wait until the train is moving and often clip my main Pack to the luggage rack. I suspect that luggage is more likely to "go missing" when in station, rather than when the train is moving. I take my Daypack and Camera bag with me, as those are the ones with the valuables and losing them would be a major problem. I also tend to have a look at the other passengers, especially if sitting in a compartment. With open seating, it's a bit of a different situation. Cheers!
I've travelled a lot solo and always take my day bag with expensive things like camera and computer with me. But otherwise, it is fine to leave it. If you have a larger bag it sits in the luggage bin at the end of the car unwatched. The chance of it going missing or getting rummaged through is very, very slight. At stations, I pay more attention since someone could walk off the train with it.
I, too, travel solo and agree with Ken. Picking up a sandwich and/or a bottle of water before you even hit the train is your best bet. When needing to use the WC, I take my shoulder bag with me, but not my suitcase, which is locked and full of laundry anyway.
When in doubt, take your pack with you, even if it's a hassle to put back. I think you will find, though, that just taking your valuables with you will be done more often than not.
I don't know how your pack closes. Most of mine close with zippers that have two thingies (I have no idea what they are called). I can use either a little luggage lock or a cable tie to lock them together. It will deter the opportunist thief. If you use cable ties, be sure to have scissors handy somewhere else. I once locked the scissors inside and had a heck of a time getting my bag open.
Those "thingies" are called "zipper pulls".
Theft is not common on trains and when it does occur it will be when the train is in the station and people are moving in and out. That is when you should be especially alert but when moving the probability is much lower.
When I travel, I don't have things in my suitcase/luggage that are anything of value. Things like my camera or i-pad are in my messenger bag along with my passport and money. The messenger bag goes with me every where I go. No one is going to get into your luggage, especially between stops. It can be a good idea to keep an eye on it while at a stop though if you haven't been able to store it overhead or near your seat.
I'm with Jo on this one, I often go have a meal on the train etc. and leave my bag behind. I don't have anything of value in my bag so even if it is taken it is not a big deal. In any case once the thief has gone through it, they will usually dump it, so there is a good chance you'll find it on the train or in the station.
A simple retractable cable lock you can affix to the overhead luggage rack and luggage locks for the zipper pulls on your pack are more than enough so you can roam the train and use the bathroom or go to the dining car if you need to, especially if you have a small purse, day bag or money belt where you can stash your money, credit cards and passport which you can easily transport to the ladies room/dining car. Anyone who might be looking for a bag to swipe would be wanting one that is easy to grab and go. The retractable cable lock also comes in handy if you need to leave your bag on one of the luggage racks that are located on the ends of the train car which are out of your immediate sight line (which can often happen if the train is very full with other passengers and bags). If your bag doesn't have zipper pulls that can be locked together with a small luggage lock and you really want to make sure no one can steal your dirty laundry or souvenirs, PacSafe sells stainless steel mesh security webs that will fit over your entire pack and will protect all the pockets on your bag. They aren't exactly the lightest thing to tote around with you on an extended trip, so you'll have to decide if the extra weight is worth the risk. You can buy the security webs at places like REI or online at Amazon.
That's why I like to use the cable ties. A pack of 100 weighs next to nothing and I don't worry about losing the key to the locks. I sometimes use them to close my suitcase when I'm not in the hotel room when I have to leave computer or binoculars, etc., and there's no safe, or one that's not big enough.