E9's have PS-68, a non self lapping brake schedule in them, and they DO have cab signals. In fact I have operated both units at different times on NJT's Raritan Valley Line in NJ in conjunction with the 142 and they do have working and compatable cab signals, at least in that particular instance. PS-68 is similar to 24-RL. The engineer has to watch the guages and manually stop the brake pipe reduction(Application) by placing the handle into "LAP" position to hold the brake application at the level he determines to be appropriate. With more modern 26/30 systems, they are self lapping, and thus the brake pipe reduction will stop on its own and maintian the application in conjunction with the handle's position in the "service" area of the handle. Why the E-9's were never upgraded to a more modern 26L system escapes me, as there are some who do not know whow to handle anything BUT 26/30 braking systems.
I know I'm getting old... My insurance company sent me only half a calendar this year!