Use very slow speed - the speed would depend on the radius of the curve and if any super-elevation has been used on the track (unlikely for very tight curves).
If that fails, then don't drive trains over that track.
In reality, just about all railways would have a minimum curve radius specified for each type of locomotive and a maximum speed set for each curve. Railways built in areas that were likely to need lots of tight curves would normally be built using narrow gauge (3ft 6in or less) as this gauge allows for tighter curves than standard gauge (4ft 8.5in) or greater.