The crossover that was the site of last Friday's derailment has been used in the past for single track operation.
The crossover was built around 2002 to faciliate construction of the Vasona line. The construction of the track junction at Children's Discovery Museum station required single tracking through the area. Also, it required VTA to reduce light rail frequency to every 15 minutes. At that time, because of funding shortfall, VTA already approved reduction of light rail service from every 10 minutes to every 12 minutes.
After construction of the Vasona line, the same crossover was used again for single tracking during the construction of carpool lanes on highway 87 in 2005. The freeway construction required rebuilding of railings adjacent to light rail tracks.