Detailed plans to take the shell off.

List the trains number from the box.  There are possibly too many variations any P.E. model for an in-depth answer to always be right. 

Pictures may help too(especially without that number)  ( tap the composing box, look to the lower right for the "attachment tool" and load, wait for "success", check off insert large size when it shows up, finish... then finish text and post.

Turn the trucks and look close near there too.

Thanks. I didnt have time to turn the engine over.  I did take out all those screws they listed in the manual, even that copper plate. Would not budge and I did not want to pry.

As you can tell the bell broke and I drilled a hole out in the bell for a tiny wire. 

I can't view the thumbnails on my device. (video works, not pics)...

Ok, I have an earlier c&o Berk.  It is also a Berk JR. like your PEx (vs exacting 1:48 scale versions).  They are very similar.

Yours has 4 screws; but don't expect it to fall apart. The fit is likely kinda tight up front at the steam chest AND it takes a near perfectly straight pull up to remove the shell..

  Don't let it jam tight if it rocks while lifting, and throw some short spurts of wiggling at it if needed. 

   I think I got mine apart for the first time by alternating prying slightly 1/32"-1/16", front & rear mostly, rocking a hair as I lifted. (Today it comes out a easier.  I also know how to tap the shell and the vibrations get it to drop... You could try that too. You might get lucky.) 

And fyi, I don't think you need to worry about keeping this one upright.

The bell & bracket can be replaced. Brasseur's had them if I recall right.(in the advertisers above or ad index.) 

(the bell does not look too bad).