Yep, I was all excited there for a bit. "Tease-T-X" aside, any of these appropriate for 1989? BC Rail is my only guess as a possibility, initially.
To add to what lock4244 has already replied, the first batch of the NSC Centerbeams to be delivered were already TTX. TTZX 861000-861999 were built in February to April 1994 and were too late for Trailer Train.
The only NSC Centerbeams delivered by 1989 were:
CNIS 623100-623259 [Rapido announced these in the second run]
CN 623260-623299 [Rapido produced these in the first run]
BCH 1000-1069
MSDR 20000-20099 [Rapido produced these in the first run]
CP 318000-318283
BCOL 873100-873174
[Source Eric Neubauer]
At least Rapido has really made an effort to produce the earliest production runs
