Virginian Elect., Photo 5

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> Gordon et all

>  

> These definitely were not standard diesel trucks, they were a GE  design.  

> The standard AAR Type B truck would not take the GE746 traction  motor used on 

> these locomotives.  (The FM "Erie-built" locos used the same  motor in an A1A 

> truck.)  Among other things, the 746 required a 42 in.  (new) diameter wheel.  

> That's one of the reasons the 752 was designed, to  fit a 40 in. wheel which 

> the EMD locos used.  The Alco S-series switchers  and RS-1 used the smaller 731 

> traction motor, but it would not rate the  horsepower/motor needed for road 

> locomotives that competed with the F-3.   Other earlier road locomotives with 

> GE electrical equipment requiring more  HP/axle had used a predecessor of the 

> 752, but I don't remember (and am not sure  I ever knew) its model number.

>  

> GE also used a smaller version of this B truck on its switching &  industrial 

> locomotives.  The easiest distinguishing spotting feature is the  absence of 

> the elliptical springs used on the AAR Type B truck.

>  

> Dave Phelps




A few notes... there's no such thing as an AAR Type-B (or Type-A) truck, let alone a standard one... just like 'Blomberg', they're railfan references to various commercial truck builder designs.  There's at least three wheelbase variations on the 'standard AAR Type-B', depending on traction motor used, 9' 4", 9' 6" and 9' 10".  

IIRC, the predecessor to the 752 was the 726... also, 746s didn't require 42" wheels (since traction motors drive their respective axle via a gear set, it's hard to see how any would require a wheel of a specific diameter)...


 
Robb Fisher
RFDI