Saw some great pics of Pat's new Work Car on the forums. Thought this work car in 2 7/8 by Jim Cohen might provide some food for thought.
There are plenty of prototypes for work cars. Arcadia Publishing has a wonderful book on New Haven Trolleys with some really nice pics of work cars. They look much like the one below. Typically the trolley lines would "repurpose" old trolleys or rolling stock used for local shipping. There are plenty of very close prototypes to the 2 7/8 gauge versions and my guess is Pat's won't look a whole lot different than the prototypes when he is done. Makes me wish all the manufacturers would stop making so many GG1's and Hudsons and start making stuff that was in quite a few neighborhoods.