Do I need some form of lock with wire or chain to secure luggage during multiple rail journeys between major cities along above route. Does one leave luggage in racks outside the actual rail-car (as we have done in France and Germany)or is there stowage space close to one's seat so that luggage is always in sight?
Your concern is right but not applicable everywhere. You should take care of your luggage but when you are at reputed hotel / holiday home, you should not much bother about all the things and you should enjoy free as the hotel staff are vigilant to protect your things.