electric locomotive

[Anonymous]

What does the nomenclature B-B+B-B or B-D+D-B mean? I know what the wheel arrangement for steam locomotives means, but I'm clueless regarding pure electric locos.

[Anonymous]

The designation B indicates a two-axle truck, C a three-axle truck and D a four-axle truck. The dash between the letters is just like a steam loco designation (2-6-2), and the plus sign indicates multiple power units under the locomotive. So B-B+B-B indicates a loco has two pair of two-axle trucks powering it.

[Anonymous]

The previous reply is correct, but in addition non-powered axles (pilot or trailing wheels) are denoted by numbers, ie: a steam classification of 4-6+6-4 would be 2-C+C-2 (like a GG-1). If all axles were powered then it would be B-C+-C-B. An interesting one is the New Haven's EP-2 passenger box cab: 1-C-1+1-C-1...a "double Prarie".

Jim