Thank you, GRJohn.
"Railsounds Lite" was in the part description/name in the parts breakdown for the sound board.
The new PRR Mikado 6-11257, #29 at http://www.lionel.com/CustomerService/ReplacementParts/index.cfm?doAction=productPartFilter&number=6911257t01&productID=07065383-871c-42e6-be64-e8d76d2e02e9
And, the recent PRR K-4 6-11265, #26 at http://www.lionel.com/CustomerService/ReplacementParts/index.cfm?doAction=productPartFilter&number=6911265T01&productID=dab7abb5-6668-4fb0-80e5-c740e04b6a42
Other parts breakdowns, such as for the Erie 0-8-0 Yard Goat 6-11247 have, of course, "Railsounds 6.0" as the part description/name .... #20 at http://www.lionel.com/CustomerService/ReplacementParts/index.cfm?doAction=productPartFilter&number=6911247T01&productID=07b59652-ffe9-4df8-b238-e711033ba103
Thanks
Jim