Pennsylvania Flyer Dead

With no responses you may want to re-word your post. 

It may help to include the item numbers for the Pennsylvania Flyer and Polar Express sets. There have been many editions of each over the past decade. This would allow the gurus on this form make detailed recommendations.

Just to be clear, it is not a good practice to mix locomotives and electronic tenders up.

Additionally, nothing beats having a reputable local train shop look at things for you. If you share your general location, we could make some recommendations on nearby service stations.

Do the trains run? Are these Lionchief engines or just conventional? It may be your transformer.

Pete

Sounds like you may have cooked the boards. Different engines/tenders with electronics such as MTH, Lionel Legacy, LionChief, etc should NEVER be swapped.

Just to clarify - is it only that the sounds do not work on each train and everything else works fine ?

Personally, I think you're down to repairing/replacing some electronics.  Swapping locomotives and tenders is typically a VERY BAD idea. 

The one exception is Lionel's IR wireless tether, those you won't damage.  They don't necessarily work, but the worst that can happen is... they don't work.

Thank you all for the advice.  My Polar Express is 630218.  I would consider replacing the soundboard with that one.  Luckily, we just got the Pennsylvania Flyer from Amazon, they are sending me a replacement for free.

Your PE Tender does not appear to have a sound board - just a speaker.

https://www.lionelsupport.com/...0b-b21e-522046fbc271

If you are lucky, you may have only burned out the speaker. The proper part is 6928653536, but any 8 ohm speaker rated about 3 Watts should do.

The actual sound board is in the PE locomotive. There are two versions and are not available through the standard parts store they have and are on the pricey side of $45

https://www.lionelsupport.com/...96-91b9-807cf715c7e6

Hope that information helps you out!

>If you are lucky, you may have only burned out the speaker. 

I'm afraid this is unlikely.