I've never heard of a Lincoln garden tractor, until now. This guy found one to fix up. They were for "Serious gardeners and after supper farmers"

Made made by National Steel & Shipbuilding Corp., San Diego, Ca. (known locally as NASSCO) after WW2 when there were no more shipbuilding contracts, so to shift to an in demand field of industry for the booming civilian post war life, they made these tractors. 

At the same time, a lot of So Cal was shifting to lawnmowers, trailers, campers, and kids bikes

This Lincoln tractor is powered by a 6 1/2 horsepower Wisconsin Model "AEH" engine and has three forward and one reverse speed Crosley transmission

here's a good look at one:https://www.northstateauctions.com/auction/316/item/lincoln-garden-tractor-68823

https://www.smokstak.com/forum/threads/nasco-lincoln.33577/

from google books 

Western Metalworking, Volumes 6-7,  page 22, 23, May 1949

In that article, it mentioned that NASSCO owned 3 tuna boats (San Diego was the home of 80% of the west coast Tuna industry, and Chicken of the Sea is still headquartered here I heard) and 4 of the Bakersfield oil wells

https://sandiego250.com/nassco/

Slide #11 on https://www.agriculture.com/machinery/ageless-iron/lawn-garden-tracts_565-sl29247

By the way, a great website for finding fun old tractors is https://www.farmcollector.com/tractors/tractors-collections