Originally Posted by
embit
Thanks!
The trip is at the end of September, so I guess there will be train running again.
Will I also need to clear security or is there an airside transfer between terminals?
After you clear immigration and customs you'll end up landside so you'll need to reclear security. Also no guarantees that the train will be up and running by September given this is Chicago after all
Regardless — you're now below MCT so it's an illegal connection so you have to be rebooked, and it's best to do it sooner rather than later while there's still space available.