Be smart about building up speed in the first place? Once that train is at full speed you might be in for a wild ride.
And, sorry to pile on, but brakes are useful also for braking.
jim
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Cross Check Nexus7, IRO Mark V, Trek 620 Nexus7, Karate Monkey half fat, IRO Model 19 fixed, Amp Research B3, Surly 1x1 half fat fixed, and more...
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SB forever