Andy - I was glad to find out what the model number stood for. I have an old 1916 TUEC catalog that shows models from 170 to 1200, with corresponding motor sizes and max. simultaneous operators, but makes no mention of suction/airflow. Now it's more clear. From what I've heard these systems operated on a maximum of about 30" waterlift, and used a 1 3/4" hose so as not to choke off too much airflow.
Given that, using one must have been a lot like an NSS "Pig" with 50 feet of hose. Probably picked things up OK, but didn't have an impressive amount of suction like a modern central vacuum.
Has anyone ever been able to use a TUEC system? I'd be curious to see what it was like, as opposed to a system based on the opposite design principle for 1910s central vacuums (narrow hose, lots and lots of suction, low CFM -- Arco Wand, for example). Betcha the TUEC actually ended up cleaning better.