They call that the 30 series pedal tractor.
They are readily available to replace the one you lost.
Should be able to find one on ebay or other toy sales and stores.
It is not crazy to want to keep your pedal tractor from the kid days.
I'm 50 and still have mine.
If you are close to Eastern Iowa I can help locate one if you want. They are not real high cost at this time. $150-$300