The figure shows the characteristic of accelerating ability in such an extreme case.
In order to achieve maximum acceleration, gears have to be first shifted either at those speeds in which the next higher gear allows for a larger acceleration than the previously engaged gear or when the maximum engine speed is reached (Fig. 3-7).
Due to the linear relationship, the maximum accelerating ability in the individual transmission levels coincides with the maximum excess traction force.
In comparison, the maxima of the excess power are shifted towards higher speeds since:
Eq. 3-12

This means that for a constant acceleration, an excess power proportional to the velocity is required.