SOLUTION

Roiling Stock Wheel Arrangements

The wheelset can be driven when torque is applied, or load-bearing otherwise. Normally rolling stock wheel arrangement layout is identified by an alpha-numeric code indicating the distribution of the wheelsets among the various bogies or partial frames, distinguishing between driven and loadbearing wheelsets.

Each group of wheelsets belonging to the same bogie or frame is marked by a letter of the alphabet if the wheelsets are driven, or by a simple number if they are load-bearing: the number or the order of the letter corresponds to the number of adjacent wheelsets few B corresponds to two wheelsets; C corresponds to three wheelsets. Moreover, the letters without subscripts refer to groups of driven wheelsets mechanically coupled to one another by means of connecting rods or gears, while the zero subscripts denotes an individually or independently controlled wheelset, each of which is driven by a motor. Some examples are listed here, classified according to traction vehicle.

• B_o + B_o or simply B_oB_o = locomotive or railcar multiple units with two bogies, each comprising two driven wheelsets with individual controls; in total, we thus have four traction motors. This is the most frequently adopted solution for trams, metros, railcar multiple units, and railway locomotives.
• BB = locomotive or railcar multiple units with two bogies, each comprising two driven coupled wheelsets. This is the preferred configuration adopted for railcar multiple units and locomotives with single-motor bogies.
• B_oB_o B_o = locomotive or railcar multiple units equipped with three bogies, each having two wheelsets with individual wheelset control. There are articulated dual car-bodies whose articulation pivot coincides with the central bogie or single car-body locomotives.
• BBB = locomotive or railcar multiple units fitted with three single-motor bogies, each with two wheelsets.
• C_oC_o = locomotive with two bogies, each with three wheelsets, having six traction motors.
• CC = locomotives with two single-motor bogies, each with three axles.