Of transformers and Whistles

[WestCelt]

I recently bought a new, in the box Williams Bachmann GP-9.  When I run it on my layout using the OLD lw transformer the engine speeds up when I try to blow the whistle.  When I try it on a club layout with a ZW transformer the Bell rings but the Whistle still doesn't.   is this a transformer issue or a whistle issue.   thanks,