They travel 200 mph and they don’t take off. Do they create downforce? How much downforce?
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In the grand scheme of aerodynamics, 200mph isn’t that fast, even more so for something not specifically designed to take off.
A large aircraft that is designed to take off, with wings(and lift from the design of the fuselage but that’s getting into fine details) designed to provide maximum lift while remaining light as possible, takes off at around 170-180mph. So a 150 ton aircraft with wings, and designed to be much less dense, needs to go the same speed. But a high speed rail train can weigh 715 tons, and is pretty dense, with no large lifting surfaces.
A much much denser train, with a shape that is not designed to provide lift, has less of a takeoff concern.
Aerodynamics are still important since as you go faster drag losses increase (exponentially or logarithmically, can’t recall offhand), and stability on crosswind is important, but speed in itself does not equal takeoff.
Interestingly though, some aerodynamic considerations like tunnels come into play. Japan redesigned their trains due to the large amount of tunnels in the country. Before with the standard round nose, if they would enter a tunnel too fast it would create a shockwave popping sound, so the trains would have to slowdown. Now the redesigned trains mimic birds that dive into water to better cut through the higher pressure in tunnels.
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