touring bikes are just like road bikes except for the frame, the wheels, the tranmission and the accessories.

Rear axle width on a touring frame is MtB std 135mm not road std 130mm.
the frame-tube wall is thicker to support the racks without cracking
Fork is beefier with more stable geometry.
Longer chains stays formed for MtB crank clearance with small rings.
Full set of threaded eyelets
Wider tyre clearance and wider brakes or disc rakes.
Stronger, wider rims, 36 spokes, MtB hubs