I am sharing my urgent passport application experience:
July 26th - Oath completed by 1030 am and downloaded eCertificate at 130 pm.
Same day, went to Surrey around 230 pm - to apply for passport via urgent processing. Officer asked for (1) Application + endorsed photos (2) Reasons / proofs for urgent passport processing (I provided my flight ticket, but also took my employment letter + employer specific letter stating my need for travel to US and why).
July 27th - Officers actually called all my two references and Guarator. Asked about my bio information like date of birth place of birth, address where I live, how long you know the applicant, why the need for urgent travel etc. Suggestion - Make sure to prepare your referrals as officers DO CALL and verify.
Same day, 2 pm picked up the passport in person at same Surrey location.
If there a different thread, please share it there as many folks can benefit from my experience.