Lionel 2033 & passenger cars curiosity question

Have seen mentioned herein that… “three passanger cars - 2421, 2422 and 2423. These being the Maplewood, Chatham and Hillside cars with silver roofs” were part of what was intended for the 2033 engines.

The 2033 being a Union Pacific engine, why would East Coast cars be part of it as a ‘set’?

thanks.

If it helps, Maplewood, Hillside, and Chatham are also places in California. [*-)]

Imposters and cheap imitations!

So speaks a Jersey boy! [;)]