If Mercury is tectonically active, that spells trouble for Kim Stanley Robinson's sci-fi city on rails, Terminator, continuously rolling away from the dawn, powered by the thermal expansion from direct sunlight.

If you need the rails running around the equator to remain straight in order to keep moving at a constant rate, all your railroad ties now have to compensate for the shifting plates.

At least that story accounted for Mercury not being tidally locked to the Sun.