options for adding sound to bachmann digital commander locos

[dr.philco]

just bought bachmann digital commander set. i already want to add sound. the locos are the emd ft-a & the emd gp40. i want to know my options for getting them to make sound hopefully without a lot more money?

[kevin2083]

Not sure about the FT, but with the GP40, there isn't much (or any) room for a speaker, unless you mill down the frame to make it fit...

Kevin