Much of Black Mountain Express flies over Exhibition Trail. For several years in the 60's and until 1978, there were actually three lifts in this location. The photo below from that era shows two double chairs and a platter/Poma approximately where current BMX Towers 4 and 5 are.
As a trivia fact, Black Mountain Express is the 6th lift in this location. The first was a single chair, then the two double chairs and poma shown below, then the Exhibition triple chair and, since 2010, the Black Mountain Express.