Energy is particularly concentrated at the steep chemical gradients of hydrothermal vents.

能量特别集中在热液喷口的陡峭化学梯度上。

In reality, they just built them at a different gauge because Spain is more mountainous and wider tracks allow for larger, more powerful engines which can climb a steeper gradient.

事实上，他们只是以不同的规格建造了它们， 因为西班牙多山，更宽的轨道允许更大、更强大的发动机， 可以爬上更陡的坡度。