I am the anonymous club member Wyatt mentions in his post above.

I have both the ACL and NYC GP-30's and love them. While George Brown was correct in his review that the volume on the prime mover sounds cannot be increased, the sounds are still audible while the engine and train are in motion. On my MTH and Lionel engines, I normally tend to reduce the volume anyhow as it tends to grow old quickly.
Very nice detail on these engines and the paint and graphics are very sharp! Kudos to Bachmann for a great new entry in the O gauge/O scale market!
I should mention too, since George raised the question in his review; the GP-30's will operate through my modified 0-27 switches. Before ordering them, I measured one of my WBB GP-38's. The GP-30's are actually about an inch shorter over the coupler faces. I've never had an issue with the 38's, so I was confident (well, sort of...) that the 30's would easily handle the curved route through my switches and that proved to be the case when I placed them on my layout.
Curt