A former engineer (who was eventually banned from the facilities for various people problems including throwing a chair at a DJ) had made dozens of these splices where almost anything that’s an analog stereo pair goes into an electrical tape covered Y connection into some kind of 4-wire shielded cable.
Out of curiosity I unwrapped the tape from one of his splices to see what was inside.
Oh, no. No no no no no no my entire facility is wired like this no no no no NOPE FUCK AAAAAAAAAHHHHHHHNOPENOPENOPEARONIWITHCHEESENONONONO
And yes this does look like the right meter– EMD just put it behind a panel, likely with a small lamp behind to light the face. I’d post the link to the original if I could find it, but it seems the metadata on railpictures.net just doesn’t match up for me to find it. The picture is of an EMD GP7 cab.