There’s a Tracking Angle article/review by Mark Ward that’s very well written.
https://trackingangle.com/music/the-original-source-does-mahler-on-steroids
Karajan Mahler Six
https://dgt.link/karajan-mahler6
I found this fascinating. I particularly enjoyed the separate machine used for the bells. If this link doesn’t open search YouTube for Karajan Mahler 6 Emile Berliner
The YT extract sounded amazing.