The three volume series called Chalk Talks Air Brake Study Course are available for full view at Hathi Trust.

https://babel.hathitrust.org/cgi/ls?field1=ocr;q1=railroad%20air%20brakes%20chalk%20talk;a=srchls;lmt=ft

also the 1919 Car Builders' Cyclopedia

https://babel.hathitrust.org/cgi/pt?id=mdp.39015006057858&;view=1up&seq=5

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Rufus Cone
Bozeman, MT