Crew visa

There is not a "transit" type crew visa, but you can apply for a China Crew Visa directly. Once you obtain a crew visa, you can remain in the aircraft during turnaround or spend some hours in a hotel.

Further to crew visa
Can a crewmember for one domestic US airline arrive in China as an OCM on a different airline

If you are a crew member of one domestic US airline, you should apply for a tourist visa to China rather than crew visa. You are not a Overseas Crew Member, the airline company won't help you to apply for crew visa.

For Crew Visa application:
Related certificate(s) as provided for in the bilateral agreement or as required by the Chinese side, a copy of agreement China Civil Aviation Administration (CAAC), or flight license number and airlines company letter. Crew members of foreign airways who perform duties on international flight operated by Chinese carriers under an exchange program should provide an Invitation Letter of Duly Authorized Unit issued by an authorized unit in China (original).