Yup. The earliest service dates for these cars is 1964 and they built them into the 70's. They are still seen on almost every CN manifest freight over the system, and most of the newsprint they haul goes to the US.
The TLT cars represent 1967-69 built prototypes. Similar cars were built as early as 1964 but originally had roofwalks and tall ladders, and had different side sills.
Later cars built in the early 1970s had slightly different side sills again and eventually went to all-welded construction.
By 1976-77 NSC was building cars with exterior posts.
