On the other hand, it could also simply be high speed test track for the PLAAF like the US Air Force has at bases in New Mexico and California, specifically at Holloman AFB in Alamorgordo, NM (which is a ten mile track), but for many of the tests, that length is not necessary. For example, such tracks are used commonly to test ejection seats.
Exactly.. There's one in Lakehurst right next to the catapults..