Hi all recently brought my second gp40 and was wondering how to install a sound card into my engines also which is the best card and sound for them
Unless you have a dummy loco or somewhere other than the powered locomotive to install sound it will be very difficult for a beginner. If I were you I would find a dummy loco that I wanted to run with the GP-40 and install the sound in there becuase there just is not enough room in the Bachmann GP-40 to install sound.
When you get the dummy loco, just follow the NMRA wiring code for DCC. The decoders come with instructions. It will not be plug and play.
Below is a good link about DCC and sound. Store the link in Favorites and do a bunch of reading on this issue.
http://www.mrdccu.com/
Look in Curriculum. You will need a DCC controller to get the max out of a decoder. Also, look in Installation.
Rich