Jingyi made a noise meant to indicate he didn't know, unbothered by the fact. Radio was barely a concept he could say he had familiarity for, and that faint niggling is from Diagad, not anything back home. Jin Butterflies might work in a time-delayed way, one direction, that might feel similar enough he'd make some better connection, but the chance of him recalling those voice-carrying butterflies right now was abysmally low.

"Can they get a message through the train's arrays?"

A moment of hesitation, then a sigh. "Or whatever it is the train does when the train's been refusing to talk to them. Not like the ICPs have lit up with Investigators going, 'Hi, we're here to talk to you about Void Travel and how Legally You Are or Are Not Engaging with it.'"

So a void radio? Sounds like a better bet, as long as there wasn't an array that was preventing it from receiving whatever message was directed its way.