This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 耊 is uncertain. It visually combines 耂 (old) and 至 (arrive), but the original semantic and phonetic roles are unclear.
The top 耂 suggests old age, and the bottom 至 suggests arriving. Picture an old person arriving at a milestone, but the exact meaning is unclear.
For テツ, imagine an old person arriving at a train station and checking the timetable: the train schedule is like a 'tetsu' (鉄, iron) rail network, but here it's just a sound hook for テツ.