What do the startup sounds replicate?

Good question

I think we need video.

Here is that strange soundd

That's the sound of the dynamo spinning up. It is a steam-powered generator that provides electrical power.

There the normal start up sounds i don't know what the wind up whistle like noise is suppose to simulate but the other sound is the compressor running building up air pressure i believe.

Alan

Yep, sounds pretty normal to me.  Must be prototypical, almost every MTH and Lionel steamer makes the same sort of startup sounds.  I have to say that I haven't been close enough when they start up to hear them for myself.