Paul:
Thanx! Glad you liked the shots!
Upton Jct. was installed during WWI to provide train service to and from the newly-constructed Camp Upton located on the present-day grounds of the BNL. The entire area was known as Upton, NY. It was a busy jct. with watering facilities, block signals and "WC" block cabin.
There was even a station there, a short distance west of the junction, called Upton Road, the former name of the main road that went into the camp. This was a short distance east of the present-day William Floyd Parkway overpass. I photographed the remains of the old wooden trestle of that road where it crossed the LIRR around 1968. I don't know if any remnants are there any longer.
A shuttle would take passengers from Upton Road into the Camp Upton station and back. Later, thru service was scheduled to bring supplies, recruits and visitors into the camp and troop trains out of the camp.
After the war it didn't do much of anything. Upton Road was discontinued as a stop and the block station was eventually placed out of service.
It was reactivated during WWII. Again, watering facilities, block signals and "CU" cabin, in service 3/1944. It reiterated what was done during WWI.
After WWII, the block station was removed and, when BNL occupied the former camp grounds, they received supplies via rail.
In May, 1968 the fan trip (top photo I posted) was run and by June, 1968 the west leg of the wye and approach tracks were removed (2nd and 3rd shots posted). The east leg of the wye and connection with the Main Line remained in service for the use of the lab.
I understand in recent years, that connection has been used to removed contaminated soil by the carload from the grounds of the lab.
Read about the LIRR and Camp Upton during WWI here:
http://www.trainsarefun.com/lirrphotos/campupton.htm
Dave