Today I accepted delivery of one of Lionel's 6-18892 locomotives; the 2328 Burlington GP-7 from the Postwar Celebration Series. Purchased new (new old stock, I suppose) from a well-known dealer. The included documentation starts off by congratulating you on your purchase and telling you to 1) put your new locomotive on the track, 2) add power with your transformer, and 3) get your GP-7 moving. This is all printed on pages 1-3 of the owner's manual. When you get to page 5, the manual instructs you to open the shell and install a 9 volt battery - presumably to engage the 'Railsounds' system.
I don't have a new 9 volt battery on hand, but I went ahead and put the locomotive on track, added power, and got the GP-7 moving - all with sound. After running a bit forward and backward (running conventionally with a Lionel transformer) I shut things down and removed the shell to have a look inside. There are, in fact, a couple of wires that terminate in a connector-clip for attaching to a 9 volt battery, but there is some kind of 'cap' in place already attached where the battery would connect - almost as if a battery is NOT to be installed.
So I'm a little bit confused. Have searched online for any clues but so far have come up empty. The manual that comes with the locomotive is a bit on the generic side - covering the GP-7, GP-9, and GP-20, none of which I am familiar with.
Is someone here familiar with this locomotive and able to advise: Does this locomotive need a battery or not?