K-3/1 Caterpillar D9 Bulldozer
This is the Caterpillar D9 which
was first manufactured in 1956; and I believe still in production. The
Lesney model was made from 1960 to 1965. It was always yellow with a red
engine. variation comes from the different coloured rollers for the
caterpillar tracks. They can be bare metal, metal painted red or yellow
or red plastic. The one to keep your eyes open for is the one with the
red plastic rollers.
Fairly usual for old Lesney caterpillar tractors of all types to have no tracks remaining, they were rubber & perished, they were also fairly fragile and very prone to breaking in play.