Kind of embarrased I dont know this.....

The engine names, and the engines themselves, can be identical. Regardless, DCS will assign each one a different DCS ID# and you can ruin them as individuals, just as any other engines.

 

If you change one engine's name, only that one's name will be changed.

 

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

I second that. Our train club has two MTH PS2 Montour SW9s, both with cab number 83. Each one can be operated independently, because in most cases DCS will assign each new engine a different ID number.