Atlas N SD35 derails

[prsllou]

The trucks seem tight and derails easily.  Any fix??

[Dave V]

The trucks seem tight and derails easily.  Any fix??

First thing I'd do is check to see if the plastic sideframe casting is sitting correctly on each truck.  Then I'd check the gauge of each wheelset.  I recall when I was in N scale and had an Atlas SD-35 I needed to tweak the gauge a bit, but I don't remember if the gauge was wide or narrow.  The good news is you can slide the wheel on the axle relatively easily to adjust the gauge.  If you don't have an NMRA N scale standards gauge, I recommend getting one before you fiddle with the wheelsets.

[C855B]

Important information missing: the recent release, or older? Chassis are different, solutions are different.

[NorsemanJack]

If by "tight," you mean that they don't rotate freely, then it is highly likely that the frame halves were tightened too much.  Remove shell, loosen screws one quarter turn each and check for improved truck movement.  Once achieved, test run without shell to confirm fix.