My con car 4-6-4 wont stay on the track

[brendenrossell]

Hi I have a older con car 4-6-4 it's brand new and it runs good other than on the sharp corners on my layout the 2 front drive weels derail I have Kato unitack are my corners to sharp or is it a problem with the loco? I really like it so I hope I can get it to run good and not just be a show peace is there anyone that has the same problem or have a fix for it?
Thanks

 

[Selector]

Chances are that the front axle is out of gauge, or a spring might be missing that keeps the axles on the engine truck pressed more firmly onto the rails, or one or both axles are not inserted correctly into their cones, or the curve is not planar transversely (between the two rails...one rail, probably the outer rail, dips, especially at a joint). I'm assuming it is no tighter than 18" radius, but maybe the engine would be happier on 22".