The former racetrack at Tanforan is bordered on one side by the former Southern Pacific mainline (currently used by the passenger service Caltrain).
Heading south, the line joins the wider rail network at Santa Clara and San Jose and on to all points on the National railroad compass.

Tanforan was, therefore, connected to the nation through the siding track that brought cars from Tanforan Park proper, to points north (San Francisco) and south (San Jose).

In 1938 the famous thoroughbred racehorse Seabiscuit boarded a special horse baggage car at the Tanforan Siding and he was shipped across the country to the East Coast on his first attempt to beat War Admiral. Large crowds came to see Seabiscuit off at the siding. The first meeting of these racing heavyweights did not happen.
Tanforan does have a dark past. In 1942, the racetrack became the Tanforan Assembly Center (the only assembly center in the San Francisco Bay Area). After the attack on Pearl Harbor, President Franklin D. Roosevelt issued executive order 9066. As a result Japanese Americans where rounded up and about 8,000 men, woman, and children where brought to Tanforan Racetrack now newly christened the Tanforan Assembly Center (one of twelve assembly centers on the West Coast).
Two-thirds of the detainees were U. S. Citizens, born and raised in the United States.

The first internees arrived on April 28, 1942. They were housed in barracks and horse stalls that reeked of manure and urine. Some families spent about eight months here before being transported, over rail, to the Topaz War Relocation Center in Utah where they remained until the end of the war.
By the fall, the detainees were being sent on a two day rail journey to the Topaz War Relocation Center. On September 9, 1942, the first group of 214 detainees entered the siding that Seabiscuit travelled on a few years earlier and entered the mainline for their trip to the wastes of northeastern Utah. On October 13, 308 detainees, the last to leave Tanforan, entered the siding and then on to Utah.

The Tanforan Assembly Center was now closed.
The site of the former track and assembly center is now a shopping mall.
In 2022 the mall was bought by a developer and there are plans to raze the mall and build a massive biotech campus.




















