If you go into any locomotive and press the 8 key - the free cam key - you can fly ANYWHERE without the invisible walls stopping you. I got a little curious and spawned at the Cumberland turntable, got into an AC44 and flew east of Cumberland.
Here's some interesting stuff I found outside of where you're allowed to drive...
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I know there are several ways to get past the invisible walls but this was all done with the free cam - you'd be insane to walk all the way down here!
I need to stop messing around and get back to scenarios when I have the chance

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