At actually looks like the support footers are ball joints! That's cool, a concept I've seen used in the textbook exercises a lot of times, but never in reality.
It allows the supports to bend slightly under the forces of the moving train. If you just cement a pole to the ground, and start tugging the end of it, the forces will be the strongest near the ground. If you add in some flexibility, you can lift the stress off the pole, allowing the force to move the joint instead of bending the pole there.