A precursor to the “Y” Stick, the train order hoop was a tool used to deliver telegraphs to trains passing by.
As a telegrapher saw a train approach his station, he would alert the dispatcher who then decided if there was a train order to be issued. If so, the telegrapher would copy the order, roll it up and clip it to the hoop, and then run to the edge of the train platform so that men on the train could receive the orders. Telegraphers delivered these hoop-bound orders to different people at different sections of the train -- at the front, the engineer, and toward the rear, the conductor.
Unfortunately, as you can probably tell by looking at the above photo of the train order hoop, it was an unwieldy tool. The person receiving an order on the train would have to swiftly catch hold of the hoop by getting an arm through it, hope the telegrapher let go of it quickly enough, and bring the whole tool aboard to unclip the train order and toss the hoop back out onto the tracks. There was a massive potential for injuries both to trainmen and telegraphers alike depending on how well the maneuver was performed.
Eventually, the train order hoop was replaced by the Y Stick, upon which a telegrapher could thread string around and to which they could attach an order that the trainman would then grab, rather than the entire hoop.