Does the On30 2-6-6-2 use the same plug and play Tsunami sound unit as the 2-4-4-2?
No. The 2-4-4-2 has the new decoder installed. The sound module is specific to the loco and plugs into the decoder. The 2-6-6-2 was issued as
non-DCC, DCC on Board and DCC Sound on Board. The 2-6-6-2 featured an 8 pin socket to accept aftermarket decoders.