The 2018 Spring Festival travel rush, known as the Chunyun, started on Feb. 1 and is regarded as the largest annual human migration on Earth. Some train journeys take up to a day because of the size of China and rail operators have been raising their game when it comes to the quality of meals provided. /VCG Photo

Some meals are prepared in kitchens on board trains like this K9441 service on Feb 6. /China Daily Photo

Packaged food, delivered by cold chain, can be kept for three days. These meals are prepared in a kitchen operated by China Railway Company. /VCG Photo

All meals must be processed under strict regulations to guarantee their quality. /VCG Photo

Some high-speed trains also offer meals dished up by chefs at city restaurants, provided the orders are made at least an hour before the train stops at the city. /VCG Photo

In the past, for most travelers enduring the Spring Festival rush, food-on-the-go was the only dining option, with many compromising with low-quality fast food and instant noodles in order to save money and quickly ease their hunger on the journey home. /Weibo Photo