I think they're the Memorex tape subsystem 3220/3228
see here :
https://mrxhist.org/docs/Ronc_5522.pdf
along with IBMs 3420 tape drives, a wonder of mechanical tape transport - able to open the tape spool case, thread the tape and then shuffle it back and forth at alarming speed past a bi-directional capstan and up and down two vacuum columns. Mesmerising to watch !
Andy