Victors not synchronized - dual motor train

[sanddrag]

We were getting really bad buzzing. Part of this is due to the Fisher Price being combined with the two Chias. At startup, I assume they are "fighting" (not spinning opposite directions, but not spining at the same speed) a little bit. Anyhow, I'm not exactly sure what we did, but we either calibrated the Victors or switched the motor polarity (and pwm values) or both. Anyhow, the buzzing is almost completely gone, only very minimal (due to drag and the FP). It was an electrical, not mechanical induced sound.