Reply to "Adding a ERR Railsound Kit"

So, John in other words

1 - leave the existing Lionel boards in place.

2 - connect the 3 position wire into ERR board, that draws information from the cereal port,

3 - then take the 4 position pin plug and plug it into the J2 (command board) 

4- then plug in the 2 position wire onto ERR Board

5 - then take the multi -position plug (purple and black wire) and plug that onto ERR Board.

Is that what you suggest?  If so would I need to connect the chuff to ERR Board or will the Lionel existing still work.

Also, I would replace the speaker.