My company manages a network of local websites, all of which run on separate subdomains. Each subdomain represents a different locality (eg brooklyn.example.com, queens.example.com).
Often, we have content that's great for multiple localities, and we post that same content on multiple sub-domains (eg brooklyn.example.com/g-train-schedule, queens.example.com/g-train-schedule).
The content is useful to both sites, but right now we're using canonical URLs to say one version on one domain is the official version (eg
<link rel="canonical" href="brooklyn.example.com/g-train-schedule"/>).
This means that even on the Queens site, the SEO benefit is being passed to the Brooklyn domain, even though the content is just as valuable for readers in Queens. If someone searches "Queens G Train Schedule", we're not coming up because our canonical URL is in Brooklyn.
So my question: is this a correct use of rel="canonical"? Is there a way to provide the SEO benefit to both sites? Would rel="alternate" be appropriate or helpful in this case?