Most trains have huge luggage allowances, making them a great alternative to planes in some situations. Like on planes, these items are often stored in overhead bins, but since you may be dealing with full-sized luggage instead of little bags, lifting them up and getting them back down can be tricky. Make sure you don’t have any one bag that feels like a ton of bricks or you may find yourself stuck in the aisle with shaky knees and a bag over your head asking strangers to bail you out. Stowing luggage in the overhead bin might make you feel so much like you’re on a plane that you decide it’s safe to put important items there, but remember that your stuff won’t be monitored by attendants and that passengers get on and off trains all the time. Carry your valuables with you at all times, especially if you plan to stretch your legs, get snacks, or nap. Most trains do (or stop at places where either vendors come aboard with food or you can quickly pop out and get some), but if you’re traveling in a country where you aren’t as familiar with the customs or train protocol, make sure you don’t find yourself on a 18-hour overnighter without a scrap of food or drink.

TL;DR in Chinese:
把重的行李平均分到每个包里面去。 贵重物品自己保管。 如果不准备带零食，要确定火车上会提供。