http://stdgauge.blogspot.com/
It reads he took 16 lbs of added weight out. Mentions board so must be PS-2. Looks like traction tires removed. The marker lights look a little different than a 381.
He gave up tractive effort by adding a 3rd motor. The half amp draw with wheels slipping is compared to wheels pulling. With no load on either configuration the amp draw would be very small for the 3rd motor maybe (.5 amp). I guess this would save the board as it would have limited draw because of the wheel slip if power is needed. A slave board with weights left in and traction tires would have made the engine a stump puller with the centipede effect of the 3rd powered wheel set.
The Pony wheels are a nice addition. The more wheels the better. The Marker lights look great and most likely would have been on the original if it ever went into production. The Flyer headlamp is better looking than the Lionel.
MTH made a model of the prototype. If the Brute ever went into production changes would have been made.