Telegraph circuits were widely used, both Morse and teletypewriter, well into the 1950s and 1960s by news services, stock brokers, railroads, pipeline companies and no doubt many other users. The use of telegraphy pre-dated carrier systems and while many of the circuits were later converted to carrier, many of them undoubtedly remained copper.
There were also the TWX services (Bell) and Telex (Western Union) which were similarly carried on telegraph circuits.
Incidentally, in later years Western Union was a big user of Bell telegraph circuits, especially within a city but also many intercity routes where they were either not able to finance their own circuits to accomodate their growth or did not feel the rate of return would be adequate.
Wes Leatherock snipped-for-privacy@aol.com