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Hi I'm Brian and I'm here to help!
The B on the Trane control board is 24 volt ac common and will relate to the C terminal on your Ecobee3. Trane is the only manufacturer that doesn't use the more common C designation for the 24 volt common terminal. Wire all others just as they should be, I assume that was a typo and you have W1 and W2 on your control board, these will relate to W and W2 on the Ecobee3. The rest are obvious. On the Ecobee3 you can wire R to Rc or Rh, either one should work and no jumpers are required.
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