To adjust the volume the shell must be removed. With a small screwdriver turn clock wise to increase sound level, we cannot warranty units turned up near or at the highest position as the speaker may be damaged. T roubleshooting American Flyer Hi-Rail cars. Check for side to side play of wheelsets when on track. Must have some play.
Some manufacturers track is too narrow in gauge.
K-line and Gargraves track is known to often be too narrow. Spread apart using pliers in reverse fashion. In some cases of S curves the radius may be so sharp that the couplers cannot move enough to prevent binding. The S is much more gentle, realistic and trouble free. E. Six wheel passenger trucks are prone to derailing if the coupler is too high, check to see if the coupler isn't touching the bottom of the car.