Young people go from Moscow to St. Petersburg and back by electric trains. They have to change 4 times. All the way takes about 16 hours.
They do not buy tickets. They either manage to escape controllers, or move from one car to another, or controllers do not approach such a big marginal crowd being afraid (like in case with football fans). That's the meaning of such a journey - economy and adventures, you'll never mess up this country with any other else.