Feng Qingxue did some calculations, and it indeed seemed a bit tight.
We're already in 1965 the Gregorian calendar, and it's early December according to the lunar calendar. It's not very realistic for Wang Fengqiao to get home in 20 days. No one can guarantee that the train won't have hiccups along the way.
Just like Wang Fengqiao said, we have no idea how many times the train will have to stop for maintenance on the way.
Both the construction workers and soldiers who built the railway had a tough time. They used their own hands to create these tracks. The railway workers who work at the railway bureaus also have it hard. They have to maintain train after train every day to ensure a smooth operation.
This time they're traveling on an express train, which is said to have an average speed of about 50 kilometers per hour and a maximum speed of 80 kilometers per hour.