If I remember correctly standard gauge is usually AC power, especially if it is an older item from pre war time. However using DC power won't hurt an AC motor, just won't work if it's pure AC, should work if it is a universal motor(means it can work on AC or DC with no problems). A Lionel post war ZW or Z or KW transformer should work with Pride Lines engine.
If you want to try DC, use a big enough DC power supply with the standard gauge motor, an H.O. power supply don't have enough watts for standard gauge, but a 12 volt motorcycle or small car battery will have the power.
Lee Fritz