You might call this a new era in transportation. Those old wooden railroad ties have been used since the 1800's. BART is slowly phasing those out in order to make way for plastic railroad ties.
It has already replaced nearly 400 wooden railroad ties with new plastic ones on its transit lines and those plastic rail ties are made out of old recycled milk jugs, grocery bags and tires.
They say the plastic ties cost about the same as the old wooden ones, but the benefit of plastic is that they are much stronger and will last up to 20 years longer. In order to make one plastic rail tie, it takes almost 3,000 plastic bags.
Bart gets the plastic ties from a company in Texas. It says part of the move to bring the plastic rail ties stems from the fact that old wooden ones don't last as long, break down in weather, and have other problems as well.
"They also are dipped in creosote, which is not an environmentally friendly kind of chemical. So, we don t have to use that with plastic ties. Altogether, the plastic ties last longer also," says BART Board of Directors President Gail Murray.
BART says its goal is to eventually replace some 14,000 wooden rail ties with the new plastic ones over the next ten years and because they will last longer, they'll get their moneys worth and put some old plastic grocery bags to good use.