My understanding is that 2200-series cars, like most CTA cars from the Pullman 2000’s on, were in married pairs, and that one 2200 could not operate by itself, because the compressors were on one car, and the batteries on the other, etc. Am I correct?
I think so, yes.
All rapid transit equipment ordered by CTA, with the exception of single cars 1-50, was built as married pairs.