rear panel 34 of the rear seat 24 slides up and down along the rails 20 thereby providing height adjustability of the rear seat 24 the pusher can therefore choose the desired configuration based on the size of the child and the pusher 39 s preferences fig3 a shows the preferred arrangement of channels 50 a and 50 b which are mounted on the backside of rear panel 34 riding on the rails 20 a and 20 b respectively for clarity only one channel of the seat 24 is shown it is understood that the two channels one on each side of the seat 24 are symmetrical the pusher can choose any point along the rails 20 and then simply tighten the hand screws 52 which extend through the channels 50 against the rails 20 alternatively as is shown in fig3 b the pusher adjusts the height of the rear seat 24 by choosing a set of detent holes not shown along the rails 20 and releasing the spring pins 52 a and 52 b into those holes these alternate embodiments include means by which the pusher can easily actuate i e disengage and engage the spring pins 52 for instance bias box 54 a can be attached to channel 50 a to provide the spring bias a trigger or button mechanism can easily be mechanically linked to the spring pin 52 depression of which would cause the spring pin 52 to disengage so that the rear seat 24 could be slid along the rails 20 in another alternate embodiment the adjustment is not made by pins at all but sheathed cables which run up and down within the rails 20 and are attached to the rear seat 24 while the present invention.