It's probably best for both parties to have them trickle in rather than delivered at once. Less yard capacity needed on both ends.
Also, today's class 1 railroads (i.e., those who would interchange with the CTA) aren't very much interested in providing "local" service to new customers, and in the CTA's case, there is no longer a working shop facility at lower 63rd yard, where the last outside connection is. So if cars were delivered via rail, one of two things would need to happen - rebuild some sort of shop you can use to prep the cars for operation at that location, and then they're ready to go, OR connect the drawbars of each pair in the yard, and drag them up to Skokie so they can be activated. Both of these options cost the CTA money, either through the new capital investment of building a shop or increased personnel & delay costs of dragging the new cars to Skokie. In the end, it's probably just cheaper to have them delivered via truck directly to Skokie.
That old car might be worth money!