BNSF Final Offer?

About 2 weeks ago I Got An Email From BNSF Saying I passed My Medical Exam. Today I Got An Email Stating I Officially Passed The Whole Pre Employment Screening (Strength/Background/etc). What stood out to me was “ BNSF is managing through the current conditions we are facing in our country and our hiring needs will remain very fluid during this time period. This means that all start dates may be subject to change.” I Was Wondering How long does it take for the final Offer & what Can that Quoted Possibly Mean?

where did u apply to? dont know how long they would wait to get you started. also think long and hard about this. we at BNSF TY&E are preparing for a strike.

Did you ever get a job offer from BNSF? If so how long did it take? I got an identical message yesterday.

I got a final job offer about three days later.