Is it strictly a tourist train or is it a long hall domestic train as well?
One of the best things about traveling by train is hanging with locals on board, spent many a night on trains in europe and asia, usually travel in coupe which is four people per berth or what the russians call platzkart which is pretty much a hostel, bunk beds with little seperators. The best thing is meeting locals, sharing food, and even getting advice and lifts to hard to reach places.