In "The Signalman," what is the critical analysis of the signalman as a character?

The mystery of the signalman's death lies in the
character's diligence and his sensitivity as a "student of natural philosophy." In this
story, Dickens employs details that stress the signalman's careful attention to his
duty, his faithful adherence to routine, and his constant vigilance. After meeting the
narrator, the signalman asks him to come to visit one night so that he can inform his
guest of all the details so that together they can, perhaps, deduce how to solve the
mystery of the voice that is heard.

Overriding all of these
characteristics of the signalman, however, is  his extreme isolation and loneliness.  In
fact, with no names given for either the signalman or the narrator, the characters are
mitigated by the detailed descriptions of the area around the train tunnel with its
"crooked prolongation" and "dripping-wet wall of jagged stone" as well as the details of
the signalman's office with its fire, official entry book, a telegraphic instrument with
its dial, face, and needles, and a little bell.

And, thus,
the Victorian conflict between the new technology, represented by the trains, and man
takes place. For, there is something foreboding and sinister about the impervious
machine that travels through the dark tunnel. In a sense, the train seems an adversary
to the sensitive man. With the train's having disturbed nature with the carving of the
tunnel as well as by the intrusion of the looming black machine, supernatural forces are
set in motion, forces too strong for the signalman to overcome as they seek what may be
retribution.

Yet, somehow the preternatural world
interferes, making the train impervious to the warnings.