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Just to clarify a bit:  The trucks do not attach directly to the locomotive frame.  They attach to the span bolster, and the span bolster attaches to the locomotive frame. The span bolster and the two trucks all pivot with the pivot swing in a horizontal plane.  That is, their pivot axes, or pivot pins are positioned vertically.   I suppose the span bolsters can accommodate some rocking motion fore and aft, and side-to-side, in addition to their pivoting in the horizontal plane.  There is that same type of action of the body relative to the trucks with a normal locomotive or freight car.  The pivot bearing is loose enough to accommodate the rocking motion.   Here is a good explanation including a drawing of a military gun with railroad wheels using span bolsters.  <a href="http://en.wikipedia.org/wiki/Span_bolster">http://en.wikipedia.org/wiki/Span_bolster</a>   Here is a heavy haul car with each end riding on four trucks.  The four trucks use a main span bolster that rides atop two secondary span bolsters.  And those secondary span bolsters ride atop the trucks.  The main span bolster has the draft gear and coupler mounted on its end, so it extends further out beyond the two end trucks <a href="http://www.flickr.com/photos/alcomike/3433929307/">http://www.flickr.com/photos/alcomike/3433929307/</a>   Here is a locomotive with the same span bolster arrangement as the TEM14 <a href="http://nick86235.smugmug.com/Trains/Away-Fixtures-2007-chasing/17789124_zLpGHg/1359194725_RXm4s76#!i=1359197007&k=LS3p8tT">http://nick86235.smugmug.com/Trains/Away-Fixtures-2007-chasing/17789124_zLpGHg/1359194725_RXm4s76#!i=1359197007&k=LS3p8tT</a>   On the TEM14, what is unique is the large prominent beam outside of the trucks.  Typically the span bolster is mostly hidden because its width is confined within the track gage.  The beam on the outside of the Russian locomotive appears to be an extension of the span bolster in order to give it support and suspension from the side sill of the locomotive frame.  With that feature, they may actually have a more complex center bearing, such as a ball joint, to accommodate the rocking and pitching motion that I mentioned above.  If that is the case, this would seem to be a highly advanced locomotive truck system.
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