RPI (http://www.rpi.edu/) is a college in Troy, New York which concentrates on degrees in engineering and science (BS, MS, PhD).
MTS comes to RPI
While RPI had been running IBM mainframes, student access was mostly via batch jobs (which is to say "punched cards"). As one might expect, catering to students in engineering and the sciences meant there was a large demand for computing on campus. In 1975 RPI had purchased a *used*(!!) IBM 360/67 from Rice University, in an attempt to do an inexpensive upgrade from their previous mainframe. That machine was simply not large enough to meet the demand, and the students made it clear that they wanted more significant improvements made to computing at RPI.
Among other things, people were interested in interactive (timesharing) use of the mainframe, instead of the batch system of OS/MVT. RPI was also running a timesharing system called "Alpha", but that was not a robust system, and it had trouble supporting even a dozen concurrent users. So, RPI went searching for a timesharing-based operating system that could stand up to the demands expected from RPI's environment. Operating systems that worked on IBM hosting mainframes would have been preferred, but in fact we looked at operating systems from Honeywell and other vendors.
At one meeting of SHARE (a conference for IBM users), Wilson Dillaway? had come across a group of guys talking about the MTS operating system. While that group didn't seem to be trying to sell anyone else on their work, Wilson was impressed with the discussions that were going on. Thus, MTS was one of the operating systems that RPI evaluated in early 1976. The committee unanimously recommended MTS over the alternatives, and MTS was running at RPI and available to users on a limited basis by fall of 1976.
(This quick overview is what I (Garance) remember of this early history. I was a freshman at the time, and I was one of two student representatives on that committee which selected MTS. I think that committee was chaired by Don Porter?, but it may have been Wilson).