> It turns out that having a "trainer" to "coach" you is not a coincidence: these two words evolved together from the rail industry to the gym.
This does not appear to be true.
Train (etymonline):
> "to discipline, teach, bring to a desired state or condition by means of instruction," 1540s, which probably is extended from the earlier sense of "draw out and manipulate in order to bring to a desired form" (Middle English trainen, attested c. 1400 as "delay, tarry" on a journey, etc.); from train (n.) For the notion of "educate" from that of "draw," compare educate.
[That train (n.) doesn't refer to the rail industry, which didn't really exist in the 1540s. It refers to a succession (as one railcar will follow another in later centuries), or to the part of your clothing that might drag on the ground behind you, or to the act of dragging anything generally. Interestingly, etymonline derives this noun from a verb train meaning to drag; given the existence of this verb, I see no reason to derive the verb train in the sense "teach" from the noun derived from the same verb in the sense "drag". The entry on the verb already noted that it isn't unexpected for "drawing" [as water from a well] to evolve into "teaching".]
Coach (wiktionary):
> The meaning "instructor/trainer" is from Oxford University slang (c. 1830) for a "tutor" who "carries" one through an exam
Coach might be a metaphor from the rail industry (or the horse-and-buggy industry), but trainer isn't.
This does not appear to be true.
Train (etymonline):
> "to discipline, teach, bring to a desired state or condition by means of instruction," 1540s, which probably is extended from the earlier sense of "draw out and manipulate in order to bring to a desired form" (Middle English trainen, attested c. 1400 as "delay, tarry" on a journey, etc.); from train (n.) For the notion of "educate" from that of "draw," compare educate.
[That train (n.) doesn't refer to the rail industry, which didn't really exist in the 1540s. It refers to a succession (as one railcar will follow another in later centuries), or to the part of your clothing that might drag on the ground behind you, or to the act of dragging anything generally. Interestingly, etymonline derives this noun from a verb train meaning to drag; given the existence of this verb, I see no reason to derive the verb train in the sense "teach" from the noun derived from the same verb in the sense "drag". The entry on the verb already noted that it isn't unexpected for "drawing" [as water from a well] to evolve into "teaching".]
Coach (wiktionary):
> The meaning "instructor/trainer" is from Oxford University slang (c. 1830) for a "tutor" who "carries" one through an exam
Coach might be a metaphor from the rail industry (or the horse-and-buggy industry), but trainer isn't.