You've got Motion Blur switched on for the obviously affected layers but the Composition Motion Blur is switched off. This explains why the Motion Blur effect is not visible during RAM previews or single frame previews.
However when you render, the Render Settings default to rendering Motion Blur for layers that have their Motion Blur property switched on. This default overrides the Composition Motion Blur switch/button.
Additionally, your Motion Blur is way too high and the Shutter Phase is off-centre. Lower the Shutter Angle (amount of Motion Blur) and set the Shutter Phase to -(1/2) of the Shutter Angle, which under normal camera circumstances is set to 180 degrees.