Not really plug and play, there's insuffcient room for the speaker. The S1 is probably actually easier though it is smaller - you cna remove the cab interior and put the speaker there. Beware these do have a wiring issue regardless of what decoder you use, the motor needs to be removed and a new orange wire added to the lower motor brush, which needs to be insulated from the frame.
The GP7 was just in the Augutst issue of Model Railroad Hobbyist, you will need to machine down the weight to make room for a speaker.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I have several Proto 2000's (Alco S1 and GP7 II) locomotives and i want to put a sound decoder in each of them. They have a plug and play socket. I want to know if there is a plug and play sound decoder for these engines.