Can You Tell How Long Is It Tail?

It is a matter of perspective. As the train enters the station, you might guess it is the same length as any other, but you don't know until a few seconds later.

As you go into a project or take any other commitment, it takes time to get the perspective that will allow you to see it's actual size and length. Plan for it to be longer and more demanding than expected, and sometimes you will be surprised for the better.