Narrative:

Night VMC taxi out of the alley in ord. We were number 2 behind another B737 and ground control issued us a taxi clearance to follow 'company' B737 to 32R for departure. On our left an emb 145 approached on B line and stopped prior to taxiway alpha. I turned our taxi light on as we taxied forward to follow the B737 onto taxiway alpha northbound. Another B737 approached form the south on taxiway alpha at a fast rate making it impossible to get behind the company B737. Once that B737 passed and with the company B737 still in sight we proceed to taxi forward (with taxi light on) and had begun our turn onto taxiway alpha. From the left the EMB145 had also moved forward and started a turn northbound on taxiway alpha at an accelerated rate. Our taxi light was on and it was apparent that he could not taxi past us without a collision. I braked hard and stopped partially through the turn as I realized the EMB145 did not see us or did not wish to yield. The EMB145 came to a stop as I transmitted 'stop!' over the radio [and] subsequently came uncomfortably close to our aircraft. At that point there was no way for us to move without striking his aircraft with our left wing and he could not move forward without running into us. Fortunately; there was adequate room for ground control to issue him instructions to turn left onto a perpendicular taxiway and taxi south on B taxiway. We were reissued taxi instructions to 32R northbound on taxiway alpha. I clarified our original instructions with ground control as they were issued 'to follow the B737' with no mention of holding for a B737 or the EMB145 (who received a taxi clearance after us). Ground control confirmed that was the case.

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Original NASA ASRS Text

Title: B737 Captain describes a ground conflict with an EMB145 at Taxiway Alpha during taxi out for takeoff at ORD.

Narrative: Night VMC taxi out of the alley in ORD. We were Number 2 behind another B737 and Ground Control issued us a taxi clearance to follow 'Company' B737 to 32R for departure. On our left an EMB 145 approached on B line and stopped prior to taxiway Alpha. I turned our taxi light on as we taxied forward to follow the B737 onto taxiway Alpha northbound. Another B737 approached form the south on taxiway Alpha at a fast rate making it impossible to get behind the company B737. Once that B737 passed and with the company B737 still in sight we proceed to taxi forward (with taxi light on) and had begun our turn onto Taxiway Alpha. From the left the EMB145 had also moved forward and started a turn northbound on Taxiway Alpha at an accelerated rate. Our taxi light was on and it was apparent that he could not taxi past us without a collision. I braked hard and stopped partially through the turn as I realized the EMB145 did not see us or did not wish to yield. The EMB145 came to a stop as I transmitted 'Stop!' over the radio [and] subsequently came uncomfortably close to our aircraft. At that point there was no way for us to move without striking his aircraft with our left wing and he could not move forward without running into us. Fortunately; there was adequate room for Ground Control to issue him instructions to turn left onto a perpendicular taxiway and taxi south on B Taxiway. We were reissued taxi instructions to 32R northbound on Taxiway Alpha. I clarified our original instructions with Ground Control as they were issued 'to follow the B737' with no mention of holding for a B737 or the EMB145 (who received a taxi clearance after us). Ground Control confirmed that was the case.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.