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Ron, I'm not a know-it all, but I am an engineer and I will always analyse. I will go into a bit more detail. Car chassis shorting out on the track will send a large current through the chassis, not the motor, so the motor will be fine. Your controller may not be, if the car is close enough to the primary / first / shortest track feed from the battery / PSU, as 100's of Amps will be flowing and the fuse will not be fast enough. So I will look elsewhere.
Now there is more than one factor that would have contributed than just fresh track glue, otherwise we would have had more failures. Typical factors are gear ratio, tyre size, motor condition / state, and that last one is something that changes from week to week. I for example had my F1 motor on the PSU @ 3V this morning, and it was drawing 2.4A, very high for a 4002. Compound that with wet track glue, and you have a good reason for my F1 motor running very hot that night. Last night it was not nearly as hot, and the only thing that seemingly changed is that the glue dried in the meantime. One factor alone (track glue) is probably not enough, but if it compounds on other factors then surely it would contribute as there will definitely be a higher load on the motor as it struggles to detach the tyres from the track. The proverbial last straw. Now this F1 motor of mine also occasionally stalls, but I can usually punch through it with the controller. I do occasionally file back the brush tips, like just before scrutineering / qualifying in the nats. Brushes may have worn in again by now, but I had no stalls last night.
There is one other scenario, if one of the terminals on your motor is shorting out to the car chassis, then it is feasible that only that terminal will melt itself out of the end-bell, as that could also constitute a short over the PSU, but that implies the current will not flow through the motor. Your armature definitely burnt, that smell was not end-bell, it was arm, so I still don't think this is what happened to your motor.
Another example of strange things that can happen to these motors - last yr. just before the nats I bought 2 new 4002s. I tried to run one of them in in water, and within 15sec the water instantly went black as the brushes dissolved. Pulled the motor out, cleaned and dried it and put it on the PSU and it was drawing about 2.5A at 3V. I took the brush gear off, cleaned the comm slots again, dried everything off, reassembled, back on PSU, same thing. Did it a couple more times,same thing. Replaced the brushes with new Gold Dust ones, problem went away.
