I'm assuming you are installing the decoder in an HO scale locomotive.
According to QSI's Kelly Dorf, the Titan's motor drive circuitry is a very efficient H-bridge chip. Which means very little heat buildup, even at 1.5 Amperes.
Electrical engineer, Mark Gurries recommends keeping the decoder away from the motor, if at all possible. The motor is going to be the hottest component in the chain.