I recently picked up two of the Athearn’s N Scale 57’ mechanical reefers with sound. The sound on these struggles a bit out of the box when in motion, but with a little added weight, these reefers perform and sound great!
No programming of the decoder is needed and they work on both DC and DCC layouts. The volume is adjustable by way of a small screw on the bottom of the car. You can watch the video review of these cars below.
These cars are available from Horizon Hobby at the link below.
Athearn N Scale 57’ Mechanical Reefers: https://bit.ly/3JfYAyr