What should have been done with Denis Grigoryev?

From the text:

"Listen. Article 1081 of the Penal Code lays down that every wilful damage of the railway line committed when it can expose the traffic on that line to danger, and the guilty party knows that an accident must be caused by it . . . (Do you understand? Knows! And you could not help knowing what this unscrewing would lead to . . .) is liable to penal servitude."