Date: 201704
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B737-900
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ZZZ
Aircraft component: Normal Brake System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Situational Awareness; Distraction; Confusion; Troubleshooting
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Returned To Gate; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: We departed the concourse on this flight for taxi and takeoff. The airport was in an eastbound configuration. We planned on getting [Runway] XYL for departure so we briefed for and executed a single engine taxi per SOP. We pushed with the ramp and taxied without issue. We contacted metering and ground without issue. Everything was normal and SOP for 3/4 of the taxi out. We ran the before takeoff checklist to the line as per SOP. I made a left on [a taxiway] without issue but the trouble started when tried to make the 90 degree right turn on to [the next taxiway]. The airplane was taxiing just fine on 1 engine. As I made the 90 degree turn; all of a sudden we lost a lot of momentum and one engine was no longer enough to keep the airplane moving. We almost stopped dead in our track during the turn. I believe the groundspeed went down to only 2 knots. I made the turn and straightened out; but the aircraft was not picking up speed like it was before this point. I had to hold 45% thrust on the running engine to keep 10 nots groundspeed. I figured we may be heading uphill; and had just made a slow 90 degree turn into the running engine so I asked my First Officer (FO) to start the left engine. He did. At this point; my attention turned to the crossing runway. We did this successfully; but I noticed even on 2 engines it seemed like I was having to use more power than normal to taxi the aircraft. After crossing the runway; we were number 3 in line for takeoff. I had several more opportunities to stop and slowly move forward as our place in line progressed. I made mention to my FO that it almost felt like we had a dragging brake. I asked him to tell the tower we were going to need to pull out of line and work a problem. At this point I called maintenance control. They directed me to call Maintenance. I spoke with Maintenance on the phone and told them what we were experiencing and what I thought it could be. They told me to bring the aircraft back to the gate. We discussed my concern of possible hot brakes. I had my flight attendants get up and go look out the window behind the wing to see if they saw or smelled anything out of the ordinary. They reported back that everything seemed fine. Maintenance asked if the airplane would move or not. I told them I could move it. It did not feel like the brakes were locked up. It just felt like it needed more power than normal to move it. Maintenance and I agreed that if it would taxi; it would be better to try to slowly taxi it back to the gate rather than send a mechanic and possible airstrips and transportation out to an active taxiway for passengers to deplane. My FO and I checked our QRH to see if there were any checklists regarding this and did not see any. We also looked at the brake cooling charts; but they were only applicable for a rejected takeoff and not our situation. We had also been sitting in this spot for approximately 25 minutes allowing the brakes to cool if in fact they were hot. Ops got us a new gate and we slowly taxied the aircraft over to it after checking to make sure that I had brakes still which I still did. We taxied to the gate without incident. Upon parking; I released the parking brake after being given the chalks in signal. After running checklists; I went downstairs to talk with the mechanics about the issue. There were 3 or 4 of them standing around the left main gear. There was some smoke coming off of the brakes and while we were standing there looking at it; the fuse plugs on I believe tire 1 blew and the tire started [deflating]. It does appear that we had a dragging brake on taxi out that started after I made the turn. We deplaned the aircraft and got a new one and continued without further incident.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B737-900 flight crew reported that taxiing required more thrust than normal enroute to the runway. After discussions with Maintenance; the crew returned to the gate where an overheated tire fuse melted; flattening the tire.