[quote=@Irredeemable]
Got an idea here:

A group of rats that have, instead of using existing areas within the mall, found loose brickwork, etc, and are masters at not only genuinely mining for raw materials, but also tearing bits of old tech apart and building crude but effective tools and machinery. Perhaps they could even subcontract to [@ClocktowerEchos]
[/quote]

The Ratpublic hires mercenaries regularly so hiring contractors and other skilled peoples is also highly likely. 
I will say that the ratpublic only has a certain amount of interest in technology which isn't actually based on clockwork or steampunk. That said, it could be that they're using you to try and "evolve" form clockwork to steampunk namely since they think it will be a massive net gain if they can get stuff like engines working.