I don't know if this answers your question but I think that becasue the towers are themselves trusees that will help brace some of hte lateral loading, also, The towers are flared at the bottom on the taller ones, , this helps in incresing the foot print of that tower, and provides more triangulation and the base where the moment of the the lateral forces will be the strongest. And because the tracl itself is a truss, it shuld help hold the towers in place, think of the track as a bridge and the supports as well, the supports. The only other lateral force i can think of at the moment would be earthquake.
Now the question is what structural provisions have been taken to prevent it from sinking. or something
*** This post was edit by Bob Dole on 12/3/99. ***