Only the most unusual parent would view high-density housing sandwiched between a major arterial street and train tracks to be an attractive place to raise school aged children.
Indeed, it would be difficult to find a developer willing to wager future profits on a marketing plan targeting parents of school-aged children. A developer is far more likely to meet open space requirements with a dog park than a playground.
If the city wants lots of children to reside at an El Camino address, it would need to offer large subsidies to their parents. Without subsidies, no matter how you zone El Camino, parents won't come.