AAR Wheel Arrangement - A1A-B+B

A1A-B+B

"A1A-B+B" means there are three trucks. The first truck has three axles, with the center one unpowered. A pair of two-axle trucks, each with both axles powered, are connected by a span bolster under the rear of the unit. The only example to date of this arrangement was a single experimental EMD SDP45.